Film(s) and/or sheet(s) made from polyester compositions containing cyclobutanediol and articles made therefrom

ABSTRACT

Described are film(s) and/or sheet(s) made using polyester compositions comprising polyesters containing (a) a dicarboxylic acid component having from about 70 to 100 mole % of terephthalic acid residues, and up to about 30 mole % of aromatic dicarboxylic acid or aliphatic dicarboxylic acid residues; and (b) a glycol component comprising 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/691,567 filed on Jun. 17, 2005, U.S. Provisional Application Ser. No. 60/731,454 filed on Oct. 28, 2005, U.S. Provisional Application Ser. No. 60/731,389, filed on Oct. 28, 2005, U.S. Provisional Application Ser. No. 60/739,058, filed on Nov. 22, 2005, and U.S. Provisional Application Ser. No. 60/738,869, filed on Nov. 22, 2005, U.S. Provisional Application Ser. No. 60/750,692 filed on Dec. 15, 2005, U.S. Provisional Application Ser. No. 60/750,693, filed on Dec. 15, 2005, U.S. Provisional Application Ser. No. 60/750,682, filed on Dec. 15, 2005, and U.S. Provisional Application Ser. No. 60/750,547, filed on Dec. 15, 2005, all of which are hereby incorporated by this reference in their entireties.

FIELD OF THE INVENTION

The present invention generally relates to film(s) and/or sheet(s) made from polyester compositions made from terephthalic acid, an ester thereof or mixtures thereof, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol having a certain combination of two or more of high impact strengths, high glass transition temperature (T_(g)), toughness, certain inherent viscosities, low ductile-to-brittle transition temperatures, good color and clarity, low densities, chemical resistance, hydrolytic stability, and long crystallization half-times, which allow them to be easily formed into film(s) and/or sheet(s).

BACKGROUND OF THE INVENTION

Poly(1,4-cyclohexylenedimethylene terephthalate (PCT), a polyester based solely on terephthalic acid or an ester thereof and 1,4-cyclohexanedimethanol, is known in the art and is commercially available. This polyester crystallizes rapidly upon cooling from the melt, making it very difficult to form amorphous articles by methods known in the art such as extrusion, injection molding, and the like. In order to slow down the crystallization rate of PCT, copolyesters can be prepared containing additional dicarboxylic acids or glycols such as isophthalic acid or ethylene glycol. These ethylene glycol- or isophthalic acid-modified PCTs are also known in the art and are commercially available.

One common copolyester used to produce films, sheeting, and molded articles is made from terephthalic acid, 1,4-cyclohexanedimethanol, and ethylene glycol. While these copolyesters are useful in many end-use applications, they exhibit deficiencies in properties such as glass transition temperature and impact strength when sufficient modifying ethylene glycol is included in the formulation to provide for long crystallization half-times. For example, copolyesters made from terephthalic acid, 1,4-cyclohexanedimethanol, and ethylene glycol with sufficiently long crystallization half-times can provide amorphous products that exhibit what is believed to be undesirably higher ductile-to-brittle transition temperatures and lower glass transition temperatures than the compositions revealed herein.

The polycarbonate of 4,4′-isopropylidenediphenol (bisphenol A polycarbonate) has been used as an alternative for polyesters known in the art and is a well known engineering molding plastic. Bisphenol A polycarbonate is a clear, high-performance plastic having good physical properties such as dimensional stability, high heat resistance, and good impact strength. Although bisphenol-A polycarbonate has many good physical properties, its relatively high melt viscosity leads to poor melt processability and the polycarbonate exhibits poor chemical resistance. It is also difficult to thermoform.

Polymers containing 2,2,4,4-tetramethyl-1,3-cyclobutanediol have also been generally described in the art. Generally, however, these polymers exhibit high inherent viscosities, and high melt viscosities and/or high Tgs (glass transition temperatures) such that the equipment used in industry can be insufficient to manufacture or post polymerization process these materials.

Thus, there is a need in the art for film(s) and/or sheet(s) comprising a polyester composition comprising at least one polyester having a combination of two or more properties chosen from the following: toughness, high impact strength, high glass transition temperatures (Tg), low ductile-to-brittle transition temperatures, good color and clarity, low densities, hydrolytic stability, chemical resistance, as well as thermoformability, long crystallization half-times, and/or thermoformability of polyesters while retaining processability on the standard equipment used the industry.

Also, in one aspect, use of certain particular polyester compositions minimizes and/or eliminates the drying step prior to melt processing and/or thermoforming.

SUMMARY OF THE INVENTION

It is believed that certain film(s) and/or sheet(s) comprising a polyester composition comprising which comprises terephthalic acid, an ester thereof or mixtures thereof; 1,4-cyclohexanedimethanol; and 2,2,4,4-tetramethyl-1,3-cyclobutanediol; with certain monomer compositions, inherent viscosities, and/or glass transition temperatures are superior to film and/or sheet made from polyesters known in the art and to polycarbonate with respect to high impact strengths, hydrolytic stability, toughness, chemical resistance, good color and clarity, long crystallization half-times, low ductile to brittle transition temperatures, lower specific gravity and/or thermoformability. These film(s) and/or sheet(s) comprise polyesters which are believed to be similar to polycarbonate in heat resistance yet they are still processable on the standard industry equipment.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.5 to         0.68 dL/g as determined in 60/40 (wt/wt)         phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at         25° C.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %;         wherein the inherent viscosity of the polyester is 0.68 dL/g or         less as determined in 60/40 (wt/wt) phenol/tetrachloroethane at         a concentration of 0.5 g/100 ml at 25° C.; and optionally,         wherein one or more branching agents is added, but when the         branching agent is added, it is added prior to or during the         polymerization of the polyester.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) from 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues, and

(c) branching agent residues;

wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and

wherein the inherent viscosity of the polyester is from 0.5 to 1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C. In one embodiment, the branching agent is added before or during polymerization of the polymer.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising:

(I) at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues, and         (II) at least one thermal stabilizer and/or reaction products         thereof;         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.5 to         1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane         at a concentration of 0.5 g/100 ml at 25° C.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) from 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol;         and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane         at a concentration of 0.5 g/100 ml at 25° C.; and         wherein the polyester has a Tg of 110 to 160° C. or 110 to         150° C. or 120 to 160° C. or 120 to 150° C. or 120 to 135° C. or         130 to 145° C., as well as other glass transition temperatures         (Tgs) described herein, as measured by a TA DSC 2920 from         Thermal Analyst Instrument at a scan rate of 20° C./min.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol;         and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         0.75 dL/g as determined in 60/40 (wt/wt)         phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at         25° C.; and         wherein the polyester has a Tg of 110 to 160° C. or 110 to         150° C. or 120 to 160° C. or 120 to 150° C. or 120 to 135° C. or         130 to 145° C., as measured by a TA DSC 2920 from Thermal         Analyst Instrument at a scan rate of 20° C./min.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) from 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         0.72 dL/g as determined in 60/40 (wt/wt)         phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at         25° C.; and         wherein the polyester has a Tg of 110 to 160° C. or 110 to         150° C. or 120 to 160° C. or 120 to 150° C. or 120 to 135° C. or         130 to 145° C., as measured by a TA DSC 2920 from Thermal         Analyst Instrument at a scan rate of 20° C./min.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         0.68 dL/g as determined in 60/40 (wt/wt)         phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at         25° C.; and         wherein the polyester has a Tg of 110 to 160° C. or 110 to         150° C. or 120 to 160° C. or 120 to 150° C. or 120 to 135° C. or         130 to 145° C., as measured by a TA DSC 2920 from Thermal         Analyst Instrument at a scan rate of 20° C./min.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) from 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         less than 0.68 dL/g as determined in 60/40 (wt/wt)         phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at         25° C.; and         wherein the polyester has a Tg of 110 to 160° C. or 110 to         150° C. or 120 to 160° C. or 120 to 150° C. or 120 to 135° C. or         130 to 145° C., as measured by a TA DSC 2920 from Thermal         Analyst Instrument at a scan rate of 20° C./min.

In one aspect, the invention relates to at least one film or sheet comprising a polyester composition comprising at least one polyester which comprises:

(a) a dicarboxylic acid component comprising:

-   -   i) 70 to 100 mole % of terephthalic acid residues;     -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having         up to 20 carbon atoms; and     -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues         having up to 16 carbon atoms; and

(b) a glycol component comprising:

-   -   i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol         residues; and     -   ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues,         wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and         wherein the inherent viscosity of the polyester is from 0.50 to         1.2 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane         at a concentration of 0.5 g/100 ml at 25° C.; and         wherein the polyester has a Tg of 120 to 135° C. as measured by         a TA DSC 2920 from Thermal Analyst Instrument at a scan rate of         20° C./min.

In one aspect, the polyester compositions useful in the invention contain at least one polycarbonate.

In one aspect, the polyester compositions useful in the invention contain no polycarbonate.

In one aspect, the polyesters useful in the film or sheet of the invention contain less than 15 mole % ethylene glycol residues, such as, for example, 0.01 to less than 15 mole % ethylene glycol residues.

In one aspect, the polyesters useful in the film or sheet of the invention contain no ethylene glycol residues.

In one aspect, the polyester compositions useful in the invention contain at least one thermal stabilizer and/or reaction products thereof.

In one aspect, the polyesters useful in the film or sheet of the invention contain no branching agent or alternatively, at least one branching agent is added either prior to or during polymerization of the polyester.

In one aspect, the polyesters useful in the film or sheet of the invention contain at least one branching agent without regard to the method or sequence in which it is added.

In one aspect, the polyesters useful in the film or sheet of the invention are made from no 1,3-propanediol, or, 1,4-butanediol, either singly or in combination. In other aspects, 1,3-propanediol or 1,4-butanediol, either singly or in combination, may be used in the making of the polyesters useful in the film or sheet of the invention.

In one aspect of the invention, the mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol useful in certain polyesters useful in the film or sheet of the invention is greater than 50 mole % or greater than 55 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol or greater than 70 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol; wherein the total mole percentage of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol is equal to a total of 100 mole %.

In one aspect of the invention, the mole % of the isomers of 2,2,4,4-tetramethyl-1,3-cyclobutanediol useful in certain polyesters useful in the film or sheet of the invention is from 30 to 70 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and from 30 to 70 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol, or from 40 to 60 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and from 40 to 60 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol, wherein the total mole percentage of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol is equal to a total of 100 mole %.

In one aspect, the polyester compositions useful in invention may be used in various types of film(s) and/or sheet(s) including but not limited to extruded film(s) and/or sheet(s), calendered film(s) and/or sheet(s), compression molded film(s) and/or sheet(s), solution casted film(s) and/or sheet(s). Methods of making film and/or sheet include but are not limited to extrusion, calendering, compression molding, and solution casting.

Also, in one aspect, use of certain polyester compositions useful in the invention minimizes and/or eliminates the drying step prior to melt processing and/or thermoforming.

In one aspect, certain polyesters useful in the film or sheet of the invention can be amorphous or semicrystalline. In one aspect, certain polyesters useful in the film or sheet of the invention can have a relatively low crystallinity. Certain polyesters useful in the film or sheet of the invention can thus have a substantially amorphous morphology, meaning that the polyesters comprise substantially unordered regions of polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the effect of comonomer on the fastest crystallization half-times of modified PCT copolyesters.

FIG. 2 is a graph showing the effect of comonomer on the brittle-to-ductile transition temperature (T_(bd)) in a notched Izod impact strength test (ASTM D256, ⅛-in thick, 10-mil notch).

FIG. 3 is a graph showing the effect of 2,2,4,4-tetramethyl-1,3-cyclobutanediol composition on the glass transition temperature (Tg) of the copolyester.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be understood more readily by reference to the following detailed description of certain embodiments of the invention and the working examples. In accordance with the purpose(s) of this invention, certain embodiments of the invention are described in the Summary of the Invention and are further described herein below. Also, other embodiments of the invention are described herein.

It is believed that polyesters and/or polyester compositions(s) useful in the film and/or sheet of the invention described herein can have a unique combination of two or more physical properties such as high impact strength, high glass transition temperatures, chemical resistance, hydrolytic stability, toughness, elevated heat stability, low ductile-to-brittle transition temperatures, good color and clarity, low densities, long crystallization half-times, and good processability thereby easily permitting them to be formed into articles. In some of the embodiments of the invention, the polyesters useful in the film or sheet of the invention have a unique combination of the properties of good impact strength, heat resistance, chemical resistance, density and/or the combination of the properties of good impact strength, heat resistance, and processability and/or the combination of two or more of the described properties, that have never before been believed to be present in a polyester.

The term “polyester”, as used herein, is intended to include “copolyesters” and is understood to mean a synthetic polymer prepared by the reaction of one or more difunctional carboxylic acids and/or multifunctional carboxylic acids with one or more difunctional hydroxyl compounds and/or multifunctional hydroxyl compounds. Typically the difunctional carboxylic acid can be a dicarboxylic acid and the difunctional hydroxyl compound can be a dihydric alcohol such as, for example, glycols and diols. The term “glycol” as used in this application includes, but is not limited to, diols, glycols, and/or multifunctional hydroxyl compounds, for example, branching agents. Alternatively, the difunctional carboxylic acid may be a hydroxy carboxylic acid such as, for example, p-hydroxybenzoic acid, and the difunctional hydroxyl compound may be an aromatic nucleus bearing 2 hydroxyl substituents such as, for example, hydroquinone. The term “residue”, as used herein, means any organic structure incorporated into a polymer through a polycondensation and/or an esterification reaction from the corresponding monomer. The term “repeating unit”, as used herein, means an organic structure having a dicarboxylic acid residue and a diol residue bonded through a carbonyloxy group. Thus, for example, the dicarboxylic acid residues may be derived from a dicarboxylic acid monomer or its associated acid halides, esters, salts, anhydrides, or mixtures thereof. Furthermore, as used herein, the term “diacid” includes multifunctional acids, for example, branching agents. As used herein, therefore, the term dicarboxylic acid is intended to include dicarboxylic acids and any derivative of a dicarboxylic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof, useful in a reaction process with a diol to make polyester. As used herein, the term “terephthalic acid” is intended to include terephthalic acid itself and residues thereof as well as any derivative of terephthalic acid, including its associated acid halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, or mixtures thereof or residues thereof useful in a reaction process with a diol to make polyester.

In one embodiment, terephthalic acid may be used as the starting material. In another embodiment, dimethyl terephthalate may be used as the starting material. In yet another embodiment, mixtures of terephthalic acid and dimethyl terephthalate may be used as the starting material and/or as an intermediate material.

The polyesters used in the film and/or sheet of the present invention typically can be prepared from dicarboxylic acids and diols which react in substantially equal proportions and are incorporated into the polyester polymer as their corresponding residues. The polyesters useful in the present invention, therefore, can contain substantially equal molar proportions of acid residues (100 mole %) and diol (and/or multifunctional hydroxyl compounds) residues (100 mole %) such that the total moles of repeating units is equal to 100 mole %. The mole percentages provided in the present disclosure, therefore, may be based on the total moles of acid residues, the total moles of diol residues, or the total moles of repeating units. For example, a polyester containing 30 mole % isophthalic acid, based on the total acid residues, means the polyester contains 30 mole % isophthalic acid residues out of a total of 100 mole % acid residues. Thus, there are 30 moles of isophthalic acid residues among every 100 moles of acid residues. In another example, a polyester containing 30 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total diol residues, means the polyester contains 30 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues out of a total of 100 mole % diol residues. Thus, there are 30 moles of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues among every 100 moles of diol residues.

It is contemplated that the compositions useful in the film and/or sheet of the invention can possess at least one of the inherent viscosity ranges described herein and at least one of the monomer ranges for the compositions described herein unless otherwise stated. It is also contemplated that compositions useful in the film and/or sheet of the invention can possess at least one of the Tg ranges described herein and at least one of the monomer ranges for the compositions described herein unless otherwise stated. It is also contemplated that compositions useful in the film and/or sheet of the invention can possess at least one of the Tg ranges described herein, at least one of the inherent viscosity ranges described herein, and at least one of the monomer ranges for the compositions described herein unless otherwise stated.

In certain embodiments, terephthalic acid, an ester thereof, such as, for example, dimethyl terephthalate, or a mixture of terephthalic acid and an ester thereof, makes up most or all of the dicarboxylic acid component used to form the polyesters useful in the film or sheet of the invention. In certain embodiments, terephthalic acid residues can make up a portion or all of the dicarboxylic acid component used to form the polyesters useful in the film or sheet of the invention at a concentration of at least 70 mole %, such as at least 80 mole %, at least 90 mole %, at least 95 mole %, at least 99 mole %, or even a mole % of 100. In certain embodiments, higher amounts of terephthalic acid can be used in order to produce a higher impact strength polyester. For the purposes of this disclosure, the terms “terephthalic acid” and “dimethyl terephthalate” are used interchangeably herein. In one embodiment, dimethyl terephthalate is part or all of the dicarboxylic acid component used to make the polyesters useful in the film or sheet of present invention. In all embodiments, ranges of from 70 to 100 mole %; or 80 to 100 mole %; or 90 to 100 mole %; or 99 to 100 mole %; or even 100 mole % terephthalic acid, and/or dimethyl terephthalate and/or mixtures thereof may be used.

In addition to terephthalic acid residues, the dicarboxylic acid component of the polyesters useful in the film or sheet of the invention can comprise up to 30 mole %, up to 20 mole %, up to 10 mole %, up to 5 mole %, or up to 1 mole % modifying aromatic dicarboxylic acids. Certain embodiments can also comprise 0.01 or more mole %, 0.1 or more mole %, 1 or more mole %, 5 or more mole % or 10 or more mole % of one or more modifying aromatic dicarboxylic acids. Thus, if present, it is contemplated that the amount of one or more modifying aromatic dicarboxylic acids can range from any of these preceding endpoint values including, for example, from 0.01 to 30 mole %, 0.01 to 20 mole %, from 0.01 to 10 mole %, from 0.01 to 5 mole % and from 0.01 to 1 mole. In one embodiment, modifying aromatic dicarboxylic acids that may be used in the present invention include but are not limited to those having up to 20 carbon atoms, and which can be linear, para-oriented, or symmetrical. Examples of modifying aromatic dicarboxylic acids which may be used in this invention include, but are not limited to, isophthalic acid, 4,4′-biphenyldicarboxylic acid, 1,4-1,5-, 2,6-, 2,7-naphthalenedicarboxylic acid, and trans-4,4′-stilbenedicarboxylic acid, and esters thereof. In one embodiment, the modifying aromatic dicarboxylic acid is isophthalic acid.

The carboxylic acid component of the polyesters useful in the film or sheet of invention can be further modified with up to 10 mole %, up to 5 mole % or up to 1 mole % of one or more aliphatic dicarboxylic acids containing 2-16 carbon atoms, such as, for example, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic and dodecanedioic dicarboxylic acids. Certain embodiments can also comprise 0.01 or more mole %, 0.1 or more mole %, 1 or more mole %, 5 or more mole %, or 10 or more mole % of one or more modifying aliphatic dicarboxylic acids. Yet another embodiment contains 0 mole % modifying aliphatic dicarboxylic acids. Thus, if present, it is contemplated that the amount of one or more modifying aliphatic dicarboxylic acids can range from any of these preceding endpoint values including, for example, from 0.01 to 10 mole % and from 0.1 to 10 mole %. The total mole % of the dicarboxylic acid component is 100 mole %.

Esters of terephthalic acid and the other modifying dicarboxylic acids or their corresponding esters and/or salts may be used instead of the dicarboxylic acids. Suitable examples of dicarboxylic acid esters include, but are not limited to, the dimethyl, diethyl, dipropyl, diisopropyl, dibutyl, and diphenyl esters. In one embodiment, the esters are chosen from at least one of the following: methyl, ethyl, propyl, isopropyl, and phenyl esters.

The 1,4-cyclohexanedimethanol may be cis, trans, or a mixture thereof, such as a cis/trans ratio of 60:40 to 40:60. In another embodiment, the trans-1,4-cyclohexanedimethanol can be present in an amount of 60 to 80 mole %.

The glycol component of the polyester portion of the polyester compositions useful in the film or sheet of the invention can contain 25 mole % or less of one or more modifying glycols which are not 2,2,4,4-tetramethyl-1,3-cyclobutanediol or 1,4-cyclohexanedimethanol; in one embodiment, the polyesters useful in the film or sheet of the invention may contain less than 15 mole % of one or more modifying glycols. In another embodiment, the polyesters useful in the film or sheet of the invention can contain 10 mole % or less of one or more modifying glycols. In another embodiment, the polyesters useful in the film or sheet of the invention can contain 5 mole % or less of one or more modifying glycols. In another embodiment, the polyesters useful in the film or sheet of the invention can contain 3 mole % or less of one or more modifying glycols. In another embodiment, the polyesters useful in the film or sheet of the invention can contain 0 mole % modifying glycols. Certain embodiments can also contain 0.01 or more mole %, 0.1 or more mole %, 1 or more mole %, 5 or more mole %, or 10 or more mole % of one or more modifying glycols. Thus, if present, it is contemplated that the amount of one or more modifying glycols can range from any of these preceding endpoint values including, for example, from 0.01 to 15 mole % and from 0.01 to 10 mole %.

Modifying glycols useful in the polyesters of the film or sheet of the invention refer to diols other than 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexanedimethanol and can contain 2 to 16 carbon atoms. Examples of suitable modifying glycols include, but are not limited to, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, p-xylene glycol, or mixtures thereof. In one embodiment, the modifying glycol is ethylene glycol. In another embodiment, modifying glycols include, but are not limited to, 1,3-propanediol and/or 1,4-butanediol. In another embodiment, ethylene glycol is excluded as a modifying diol. In another embodiment, 1,3-propanediol and 1,4-butanediol are excluded as modifying diols. In another embodiment, 2,2-dimethyl-1,3-propanediol is excluded as a modifying diol.

The polyesters and/or the polycarbonates useful in the polyester compositions useful in the film or sheet of the invention can comprise from 0 to 10 mole percent, for example, from 0.01 to 5 mole percent, from 0.01 to 1 mole percent, from 0.05 to 5 mole percent, from 0.05 to 1 mole percent, or from 0.1 to 0.7 mole percent, based the total mole percentages of either the diol or diacid residues; respectively, of one or more residues of a branching monomer, also referred to herein as a branching agent, having 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof. In certain embodiments, the branching monomer or agent may be added prior to and/or during and/or after the polymerization of the polyester. The polyester(s) useful in the film or sheet of the invention can thus be linear or branched. The polycarbonate can also be linear or branched. In certain embodiments, the branching monomer or agent may be added prior to and/or during and/or after the polymerization of the polycarbonate.

Examples of branching monomers include, but are not limited to, multifunctional acids or multifunctional alcohols such as trimellitic acid, trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid and the like. In one embodiment, the branching monomer residues can comprise 0.1 to 0.7 mole percent of one or more residues chosen from at least one of the following: trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1,2,6-hexanetriol, pentaerythritol, trimethylolethane, and/or trimesic acid. The branching monomer may be added to the polyester reaction mixture or blended with the polyester(s) in the form of a concentrate as described, for example, in U.S. Pat. Nos. 5,654,347 and 5,696,176, whose disclosure regarding branching monomers is incorporated herein by reference.

In other aspects of the invention, the inherent viscosity(ies) of the polyesters useful in the film or sheet of the invention can be at least one of the following ranges: 0.50 to 1.2 dL/g; 0.50 to 1.1 dL/g; 0.50 to 1 dL/g; 0.50 to less than 1 dL/g; 0.50 to 0.98 dL/g; 0.50 to 0.95 dL/g; 0.50 to 0.90 dL/g; 0.50 to 0.85 dL/g; 0.50 to 0.80 dL/g; 0.50 to 0.75 dL/g; 0.50 to less than 0.75 dL/g; 0.50 to 0.72 dL/g; 0.50 to 0.70 dL/g; 0.50 to less than 0.70 dL/g; 0.50 to 0.68 dL/g; 0.50 to less than 0.68 dL/g; 0.50 to 0.67 dL/g; 0.50 to 0.66 dL/g; 0.50 to 0.65 dL/g; 0.55 to 1.2 dL/g; 0.55 to 1.1 dL/g; 0.55 to 1 dL/g; 0.55 to less than 1 dL/g; 0.55 to 0.98 dL/g; 0.55 to 0.95 dL/g; 0.55 to 0.90 dL/g; 0.55 to 0.85 dL/g; 0.55 to 0.80 dL/g; 0.55 to 0.75 dL/g; 0.55 to less than 0.75 dL/g; 0.55 to 0.72 dL/g; 0.55 to 0.70 dL/g; 0.55 to less than 0.70 dL/g; 0.55 to 0.68 dL/g; 0.55 to less than 0.68 dL/g; 0.55 to 0.65 dL/g; 0.58 to 1.2 dL/g; 0.58 to 1.1 dL/g; 0.58 to 1 dL/g; 0.58 to less than 1 dL/g; 0.58 to 0.98 dL/g; 0.58 to 0.95 dL/g; 0.58 to 0.90 dL/g; 0.58 to 0.85 dL/g; 0.58 to 0.80 dL/g; 0.58 to 0.75 dL/g; 0.58 to less than 0.75 dL/g; 0.58 to 0.72 dL/g; 0.58 to 0.70 dL/g; 0.58 to less than 0.70 dL/g; 0.58 to 0.68 dL/g; 0.58 to less than 0.68 dL/g; 0.58 to 0.65 dL/g; 0.60 to 1.2 dL/g; 0.60 to 1.1 dL/g; 0.60 to 1 dL/g; 0.60 to less than 1 dL/g; 0.60 to 0.98 dL/g; 0.60 to 0.95 dL/g; 0.60 to 0.90 dL/g; 0.60 to 0.85 dL/g; 0.60 to 0.80 dL/g; 0.60 to 0.75 dL/g; 0.60 to less than 0.75 dL/g; 0.60 to 0.72 dL/g; 0.60 to 0.70 dL/g; 0.60 to less than 0.70 dL/g; 0.60 to 0.68 dL/g; 0.60 to less than 0.68 dL/g; 0.60 to 0.65 dL/g; greater than 0.60 to less than 0.80 dL/g; greater than 0.60 to 0.75 dL/g; greater than 0.60 to less than 0.75 dL/g; greater than 0.60 to 0.72 dL/g; 0.62 to 1.2 dL/g; 0.62 to 1.1 dL/g; 0.62 to 1 dL/g; 0.62 to less than 1 dL/g; 0.62 to 0.98 dL/g; 0.62 to 0.95 dL/g; 0.62 to 0.90 dL/g; 0.62 to 0.85 dL/g; 0.62 to 0.80 dL/g; 0.62 to less than 0.80 dL/g; 0.62 to 0.75 dL/g; 0.62 to less than 0.75 dL/g; 0.62 to 0.72 dL/g; 0.62 to 0.70 dL/g; 0.62 to less than 0.70 dL/g; 0.62 to 0.68 dL/g; 0.62 to less than 0.68 dL/g; 0.62 to 0.65 dL/g; 0.65 to 1.2 dL/g; 0.65 to 1.1 dL/g; 0.65 to 1 dL/g; 0.65 to less than 1 dL/g; 0.65 to 0.98 dL/g; 0.65 to 0.95 dL/g; 0.65 to 0.90 dL/g; 0.65 to 0.85 dL/g; 0.65 to 0.80 dL/g; 0.65 to 0.75 dL/g; 0.65 to less than 0.75 dL/g; 0.65 to 0.72 dL/g; 0.65 to 0.70 dL/g; 0.65 to less than 0.70 dL/g; 0.68 to 1.2 dL/g; 0.68 to 1.1 dL/g; 0.68 to 1 dL/g; 0.68 to less than 1 dL/g; 0.68 to 0.98 dL/g; 0.68 to 0.95 dL/g; 0.68 to 0.90 dL/g; 0.68 to 0.85 dL/g; 0.68 to 0.80 dL/g; 0.68 to 0.75 dL/g; 0.68 to less than 0.75 dL/g; 0.68 to 0.72 dL/g; greater than 0.76 dL/g to 1.2 dL/g; greater than 0.76 dL/g to 1.1 dL/g; greater than 0.76 dL/g to 1 dL/g; greater than 0.76 dL/g to less than 1 dL/g; greater than 0.76 dL/g to 0.98 dL/g; greater than 0.76 dL/g to 0.95 dL/g; greater than 0.76 dL/g to 0.90 dL/g; greater than 0.80 dL/g to 1.2 dL/g; greater than 0.80 dL/g to 1.1 dL/g; greater than 0.80 dL/g to 1 dL/g; greater than 0.80 dL/g to less than 1 dL/g; greater than 0.80 dL/g to 1.2 dL/g; greater than 0.80 dL/g to 0.98 dL/g; greater than 0.80 dL/g to 0.95 dL/g; greater than 0.80 dL/g to 0.90 dL/g.

For certain embodiments of the invention, the polyesters useful in the film(s) and/or sheet(s) useful in the invention may exhibit at least one of the following inherent viscosities: 0.10 to 0.68 dL/g; 0.10 to less than 0.68 dL/g; 0.10 to 0.65 dL/g; 0.10 to less than 0.65 dL/g; 0.10 to 0.60 dL/g; 0.10 to less than 0.60 dL/g; 0.10 to 0.58 dL/g; 0.10 to less than 0.58 dL/g; 0.10 to 0.55 dL/g; 0.10 to less than 0.55 dL/g; 0.10 to 0.50 dL/g; 0.10 to less than 0.50 dL/g; 0.10 to 0.45 dL/g; 0.10 to greater than 0.42 dL/g; 0.10 to 0.40 dL/g; 0.10 to 0.35 dL/g; 0.20 to 0.68 dL/g; 0.20 to less than 0.68 dL/g; 0.20 to 0.65 dL/g; 0.20 to less than 0.65 dL/g; 0.20 to 0.60 dL/g; 0.20 to less than 0.60 dL/g; 0.20 to 0.58 dL/g; 0.20 to less than 0.58 dL/g; 0.20 to 0.55 dL/g; 0.20 to less than 0.55 dL/g; 0.20 to 0.50 dL/g; 0.20 to less than 0.50 dL/g; 0.20 to 0.45 dL/g; 0.20 to greater than 0.42 dL/g; 0.20 to 0.40 dL/g; 0.20 to 0.35 dL/g; 0.35 to 0.68 dL/g; 0.35 to less than 0.68 dL/g; 0.35 to 0.65 dL/g; 0.35 to less than 0.65 dL/g; 0.35 to 0.60 dL/g; 0.35 to less than 0.60 dL/g; 0.35 to 0.58 dL/g; 0.35 to less than 0.58 dL/g; 0.35 to 0.55 dL/g; 0.35 to less than 0.55 dL/g; 0.35 to 0.50 dL/g; 0.35 to less than 0.50 dL/g; 0.35 to 0.45 dL/g; 0.35 to greater than 0.42 dL/g; 0.35 to 0.40 dL/g; 0.40 to 0.68 dL/g; 0.40 to less than 0.68 dL/g; 0.40 to 0.65 dL/g; 0.40 to less than 0.65 dL/g; 0.40 to 0.60 dL/g; 0.40 to less than 0.60 dL/g; 0.40 to 0.58 dL/g; 0.40 to less than 0.58 dL/g; 0.40 to 0.55 dL/g; 0.40 to less than 0.55 dL/g; 0.40 to 0.50 dL/g; 0.40 to less than 0.50 dL/g; 0.40 to 0.45 dL/g; greater than 0.42 to 0.68 dL/g; greater than 0.42 to less than 0.68 dL/g; greater than 0.42 to 0.65 dL/g; greater than 0.42 to less than 0.65 dL/g; greater than 0.42 to 0.60 dL/g; greater than 0.42 to less than 0.60 dL/g; greater than 0.42 to 0.58 dL/g; greater than 0.42 to less than 0.58 dL/g; greater than 0.42 to 0.55 dL/g; greater than 0.42 to less than 0.55 dL/g; greater than 0.42 to 0.50 dL/g; and greater than 0.42 to less than 0.50 dL/g.

For certain embodiments of the invention, the polyesters useful in the film(s) and/or sheet(s) useful in the invention may exhibit at least one of the following inherent viscosities: 0.45 to 0.68 dL/g; 0.45 to less than 0.68 dL/g; 0.45 to 0.65 dL/g; 0.45 to less than 0.65 dL/g; 0.45 to 0.60 dL/g; 0.45 to less than 0.60 dL/g; 0.45 to 0.58 dL/g; 0.45 to less than 0.58 dL/g; 0.45 to 0.55 dL/g; 0.45 to less than 0.55 dL/g; 0.45 to 0.50 dL/g; 0.45 to less than 0.50 dL/g; 0.50 to 0.68 dL/g; 0.50 to less than 0.68 dL/g; 0.50 to 0.65 dL/g; 0.50 to less than 0.65 dL/g; 0.50 to 0.60 dL/g; 0.50 to less than 0.60 dL/g; 0.50 to 0.58 dL/g; 0.50 to less than 0.58 dL/g; 0.50 to 0.55 dL/g; 0.50 to less than 0.55 dL/g; 0.55 to 0.68 dL/g; 0.55 to less than 0.68 dL/g; 0.55 to 0.65 dL/g; 0.55 to less than 0.65 dL/g; 0.55 to 0.60 dL/g; 0.55 to less than 0.60 dL/g; 0.60 to 0.68 dL/g; 0.60 to less than 0.68 dL/g; 0.60 to 0.65 dL/g; and 0.60 to less than 0.65 dL/g.

Inherent viscosity for the polyesters useful the film or sheet of the invention is determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.

In other aspects of the invention, the glycol component for the polyesters useful in the film or sheet of the invention include but are not limited to at least one of the following ranges: 40 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 60 mole % 1,4-cyclohexanedimethanol; or 45 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 55 mole % 1,4-cyclohexanedimethanol; or greater than 50 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to less than 50 mole % 1,4-cyclohexanedimethanol; or 50 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 50 mole % 1,4-cyclohexanedimethanol; or 55 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 45 mole % 1,4-cyclohexanedimethanol; or 40 to 60 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40 to 60 mole % 1,4-cyclohexanedimethanol; or 40 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 60 mole % 1,4-cyclohexanedimethanol; or 45 to 60 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40 to 55 mole % 1,4-cyclohexanedimethanol; or 45 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 55 mole % 1,4-cyclohexanedimethanol; or greater than 45 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and from 45 to less than 55 mole % 1,4-cyclohexanedimethanol; or 46 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 54 mole % 1,4-cyclohexanedimethanol; or 40 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 60 mole % 1,4-cyclohexanedimethanol; or 40 to 50 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 50 to 60 mole % 1,4-cyclohexanedimethanol; or 45 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 55 mole % 1,4-cyclohexanedimethanol; or 45 to 60 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40 to 55 mole % 1,4-cyclohexanedimethanol; or 46 to 60 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40 to 54 mole % 1,4-cyclohexanedimethanol; or 46 to 54 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 46 to 54 mole % 1,4-cyclohexanedimethanol; or greater than 46 up to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 46 to less than 55 mole % 1,4-cyclohexanedimethanol; or greater than 50 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to less than 50 mole % 1,4-cyclohexanedimethanol; or 50 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 50 mole % 1,4-cyclohexanedimethanol; or 55 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 45 mole % 1,4-cyclohexanedimethanol; based on the total mole % of the glycol component of the polyesters useful in the film or sheet of the invention.

For the desired polyester, the molar ratio of cis/trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol can vary from the pure form of each or mixtures thereof. In certain embodiments, the molar percentages for cis and/or trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol are greater than 50 mole % cis and less than 50 mole % trans; or greater than 55 mole % cis and less than 45 mole % trans; or 30 to 70 mole % cis and 70 to 30 mole % trans; or 40 to 60 mole % cis and 60 to 40 mole % trans; or 50 to 70 mole % trans and 50 to 30 mole % cis or 50 to 70 mole % cis and 50 to 30 mole % trans; or 60 to 70 mole % cis and 30 to 40 mole % trans; or greater than 70 mole % cis and less than 30 mole % trans; wherein the total sum of the mole percentages for cis- and trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol is equal to 100 mole %.

The molar ratio of cis/trans 1,4-cyclohexandimethanol can vary within the range of 50/50 to 0/100, for example, between 40/60 to 20/80.

In other aspects of the invention, the Tg of the polyesters useful in the film or sheet of the invention can be at least one of the following ranges: 85 to 200° C.; 85 to 190° C.; 85 to 180° C.; 85 to 170° C.; 85 to 160° C.; 85 to 155° C.; 85 to 150° C.; 85 to 145° C.; 85 to 140° C.; 85 to 138° C.; 85 to 135° C.; 85 to 130° C.; 85 to 125° C.; 85 to 120° C.; 85 to 115° C.; 85 to 110° C.; 85 to 105° C.; 85 to 100° C.; 85 to 95° C.; 85 to 90° C.; 90 to 200° C.; 90 to 190° C.; 90 to 180° C.; 90 to 170° C.; 90 to 160° C.; 90 to 155° C.; 90 to 150° C.; 90 to 145° C.; 90 to 140° C.; 90 to 138° C.; 90 to 135° C.; 90 to 130° C.; 90 to 125° C.; 90 to 120° C.; 90 to 115° C.; 90 to 110° C.; 90 to 105° C.; 90 to 100° C.; 90 to 95° C.; 95 to 200° C.; 95 to 190° C.; 95 to 180° C.; 95 to 170° C.; 95 to 160° C.; 95 to 155° C.; 95 to 150° C.; 95 to 145° C.; 95 to 140° C.; 95 to 138° C.; 95 to 135° C.; 95 to 130° C.; 95 to 125° C.; 95 to 120° C.; 95 to 115° C.; 95 to 110° C.; 95 to 105° C.; 95 to 100° C.; 100 to 200° C.; 100 to 190° C.; 100 to 180° C.; 100 to 170° C.; 100 to 160° C.; 100 to 155° C.; 100 to 150° C.; 100 to 145° C.; 100 to 140° C.; 100 to 138° C.; 100 to 135° C.; 100 to 130° C.; 100 to 125° C.; 100 to 120° C.; 100 to 115° C.; 100 to 110° C.; 105 to 200° C.; 105 to 190° C.; 105 to 180° C.; 105 to 170° C.; 105 to 160° C.; 105 to 155° C.; 105 to 150° C.; 105 to 145° C.; 105 to 140° C.; 105 to 138° C.; 105 to 135° C.; 105 to 130° C.; 105 to 125° C.; 105 to 120° C.; 105 to 115° C.; 105 to 110° C.; 110 to 200° C.; 110 to 190° C.; 110 to 180° C.; 110 to 170° C.; 110 to 160° C.; 110 to 155° C.; 110 to 150° C.; 110 to 145° C.; 110 to 140° C.; 110 to 138° C.; 110 to 135° C.; 110 to 130° C.; 110 to 125° C.; 110 to 120° C.; 110 to 115° C.; 115 to 200° C.; 115 to 190° C.; 115 to 180° C.; 115 to 170° C.; 115 to 160° C.; 115 to 155° C.; 115 to 150° C.; 115 to 145° C.; 115 to 140° C.; 115 to 138° C.; 115 to 135° C.; 110 to 130° C.; 115 to 125° C.; 115 to 120° C.; 120 to 200° C.; 120 to 190° C.; 120 to 180° C.; 120 to 170° C.; 120 to 160° C.; 120 to 155° C.; 120 to 150° C.; 120 to 145° C.; 120 to 140° C.; 120 to 138° C.; 120 to 135° C.; 120 to 130° C.; 125 to 200° C.; 125 to 190° C.; 125 to 180° C.; 125 to 170° C.; 125 to 160° C.; 125 to 155° C.; 125 to 150° C.; 125 to 145° C.; 125 to 140° C.; 125 to 138° C.; 125 to 135° C.; 127 to 200° C.; 127 to 190° C.; 127 to 180° C.; 127 to 170° C.; 127 to 160° C.; 127 to 150° C.; 127 to 145° C.; 127 to 140° C.; 127 to 138° C.; 127 to 135° C.; 130 to 200° C.; 130 to 190° C.; 130 to 180° C.; 130 to 170° C.; 130 to 160° C.; 130 to 155° C.; 130 to 150° C.; 130 to 145° C.; 130 to 140° C.; 130 to 138° C.; 130 to 135° C.; 135 to 200° C.; 135 to 190° C.; 135 to 180° C.; 135 to 170° C.; 135 to 160° C.; 135 to 155° C.; 135 to 150° C.; 135 to 145° C.; 135 to 140° C.; 140 to 200° C.; 140 to 190° C.; 140 to 180° C.; 140 to 170° C.; 140 to 160° C.; 140 to 155° C.; 140 to 150° C.; 140 to 145° C.; 148 to 200° C.; 148 to 190° C.; 148 to 180° C.; 148 to 170° C.; 148 to 160° C.; 148 to 155° C.; 148 to 150° C.; 150 to 200° C.; 150 to 190° C.; 150 to 180° C.; 150 to 170° C.; 150 to 160; 155 to 190° C.; 155 to 180° C.; 155 to 170° C.; and 155 to 165° C.

Glass transition temperature (Tg) was determined using a TA DSC 2920 from Thermal Analyst Instrument at a scan rate of 20° C./min.

Because of the long crystallization half-times (e.g., greater than 5 minutes) at 170° C. exhibited by certain polyesters useful in the film or sheet of the present invention, it can be possible to produce articles, including but not limited to, injection molded parts, injection blow molded articles, injection stretch blow molded articles, extruded film, extruded sheet, extrusion blow molded articles and fibers. The polyesters useful in the film or sheet of the invention can be amorphous or semicrystalline. In one aspect, certain polyesters useful in the film or sheet of the invention can have a relatively low crystallinity. Certain polyesters useful in the film or sheet of the invention can thus have a substantially amorphous morphology, meaning that the polyesters comprise substantially unordered regions of polymer.

In one embodiment, an “amorphous” polyester can have a crystallization half-time of greater than 5 minutes at 170° C. or greater than 10 minutes at 170° C. or greater than 50 minutes at 170° C. or greater than 100 minutes at 170° C. In one embodiment, of the invention, the crystallization half-times are greater than 1,000 minutes at 170° C. In another embodiment of the invention, the crystallization half-times of the polyesters useful in the film or sheet of the invention are greater than 10,000 minutes at 170° C. The crystallization half time of the polyester, as used herein, may be measured using methods well-known to persons of skill in the art. For example, the crystallization half time of the polyester, t_(1/2), can be determined by measuring the light transmission of a sample via a laser and photo detector as a function of time on a temperature controlled hot stage. This measurement can be done by exposing the polymers to a temperature, T_(max), and then cooling it to the desired temperature. The sample can then be held at the desired temperature by a hot stage while transmission measurements were made as a function of time. Initially, the sample can be visually clear with high light transmission, and becomes opaque as the sample crystallizes. The crystallization half-time is the time at which the light transmission is halfway between the initial transmission and the final transmission. T_(max) is defined as the temperature required to melt the crystalline domains of the sample (if crystalline domains are present). The sample can be heated to T_(max) to condition the sample prior to crystallization half time measurement. The absolute Tmax temperature is different for each composition. For example PCT can be heated to some temperature greater than 290° C. to melt the crystalline domains.

As shown in Table 1 and FIG. 1 of the Examples, 2,2,4,4-tetramethyl-1,3-cyclobutanediol is more effective than other comonomers such ethylene glycol and isophthalic acid at increasing the crystallization half-time, i.e., the time required for a polymer to reach half of its maximum crystallinity. By decreasing the crystallization rate of PCT, i.e. increasing the crystallization half-time, amorphous articles based on modified PCT may be fabricated by methods known in the art such as extrusion, injection molding, and the like. As shown in Table 1, these materials can exhibit higher glass transition temperatures and lower densities than other modified PCT copolyesters.

The polyesters can exhibit an improvement in toughness combined with processability for some of the embodiments of the invention. For example, lowering the inherent viscosity slightly of the polyesters useful in the film or sheet of the invention results in a more processable melt viscosity while retaining good physical properties of the polyesters such as toughness and heat resistance.

Increasing the content of 1,4-cyclohexanedimethanol in a copolyester based on terephthalic acid, ethylene glycol, and 1,4-cyclohexanedimethanol can improve toughness, which can be determined by the brittle-to-ductile transition temperature in a notched Izod impact strength test as measured by ASTM D256. This toughness improvement, by lowering of the brittle-to-ductile transition temperature with 1,4-cyclohexanedimethanol, is believed to occur due to the flexibility and conformational behavior of 1,4-cyclohexanedimethanol in the copolyester. Incorporating 2,2,4,4-tetramethyl-1,3-cyclobutanediol into PCT is believed to improve toughness, by lowering the brittle-to-ductile transition temperature, as shown in Table 2 and FIG. 2 of the Examples.

In one embodiment, the melt viscosity of the polyester(s) useful in the film or sheet of the invention is less than 30,000 poise as measured a 1 radian/second on a rotary melt rheometer at 290° C. In another embodiment, the melt viscosity of the polyester(s) useful in the film or sheet of the invention is less than 20,000 poise as measured a 1 radian/second on a rotary melt rheometer at 290° C.

In one embodiment, the melt viscosity of the polyester(s) useful in the film or sheet of the invention is less than 15,000 poise as measured at 1 radian/second (rad/sec) on a rotary melt rheometer at 290° C. In one embodiment, the melt viscosity of the polyester(s) useful in the film or sheet of the invention is less than 10,000 poise as measured at 1 radian/second (rad/sec) on a rotary melt rheometer at 290° C. In another embodiment, the melt viscosity of the polyester(s) useful in the film or sheet of the invention is less than 6,000 poise as measured at 1 radian/second on a rotary melt rheometer at 290° C. Viscosity at rad/sec is related to processability. Typical polymers have viscosities of less than 10,000 poise as measured at 1 radian/second when measured at their processing temperature. Polyesters are typically not processed above 290 C. Polycarbonate is typically processed at 290 C. The viscosity at 1 rad/sec of a typical 12 melt flow rate polycarbonate is 7000 poise at 290 C.

The present polyesters useful in the film or sheet of the invention can possess one or more of the following properties. Notched Izod impact strength, as described in ASTM D256, is a common method of measuring toughness. In one embodiment, the polyesters useful in the film or sheet of the invention exhibit a impact strength of at least 150 J/m (3 ft-lb/in) at 23° C. with a 10-mil notch in a 3.2 mm (⅛-inch) thick bar determined according to ASTM D256; in one embodiment, the polyesters useful in the film or sheet of the invention exhibit a notched Izod impact strength of at least (400 J/m) 7.5 ft-lb/in at 23° C. with a 10-mil notch in a 3.2 mm (⅛-inch) thick bar determined according to ASTM D256; in one embodiment, the polyesters useful in the film or sheet of the invention exhibit a notched Izod impact strength of at least 1000 J/m (18 ft-lb/in) at 23° C. with a 10-mil notch in a 3.2 mm (⅛-inch) thick bar determined according to ASTM D256. In one embodiment, the polyesters useful in the film or sheet of the invention exhibit a notched Izod impact strength of at least 150 J/m (3 ft-lb/in) at 23° C. with a 10-mil notch in a 6.4 mm (¼-inch) thick bar determined according to ASTM D256; in one embodiment, the polyesters useful in the film or sheet of the invention exhibit a notched Izod impact strength of at least (400 J/m) 7.5 ft-lb/in at 23° C. with a 10-mil notch in a 6.4 mm (¼-inch) thick bar determined according to ASTM D256; in one embodiment, the polyesters useful in the film or sheet of the invention exhibit a notched Izod impact strength of at least 1000 J/m (18 ft-lb/in) at 23° C. with a 10-mil notch in a 6.4 mm (¼-inch) thick bar determined according to ASTM D256.

In another embodiment, certain polyesters useful in the film or sheet of the invention can exhibit an increase in notched Izod impact strength when measured at 0° C. of at least 3% or at least 5% or at least 10% or at least 15% as compared to the notched Izod impact strength when measured at −5° C. with a 10-mil notch in a ⅛-inch thick bar determined according to ASTM D256. In addition, certain other polyesters of the invention can also exhibit a retention of notched Izod impact strength within plus or minus 5% when measured at 0° C. through 30° C. with a 10-mil notch in a ⅛-inch thick bar determined according to ASTM D256.

In yet another embodiment, certain polyesters useful in the film or sheet of the invention can exhibit a retention in notched Izod impact strength with a loss of no more than 70% when measured at 23° C. with a 10-mil notch in a ¼-inch thick bar determined according to ASTM D256 as compared to notched Izod impact strength for the same polyester when measured at the same temperature with a 10-mil notch in a ⅛-inch thick bar determined according to ASTM D256.

In one embodiment, the polyesters useful in the film or sheet of the invention can exhibit a ductile-to-brittle transition temperature of less than 0° C. based on a 10-mil notch in a ⅛-inch thick bar as defined by ASTM D256.

In one embodiment, the polyesters useful in the film or sheet of the invention can exhibit at least one of the following densities as determined using a gradient density column at 23° C.: a density of less than 1.2 g/ml at 23° C.; a density of less than 1.18 g/ml at 23° C.; a density of 0.8 to 1.3 g/ml at 23° C.; a density of 0.80 to 1.2 g/ml at 23° C.; a density of 0.80 to less than 1.2 g/ml at 23° C.; a density of 1.0 to 1.3 g/ml at 23° C.; a density of 1.0 to 1.2 g/ml at 23° C.; a density of 1.0 to 1.1 g/ml at 23° C.; a density of 1.13 to 1.3 g/ml at 23° C.; a density of 1.13 to 1.2 g/ml at 23° C.

In one embodiment, the polyesters useful in film or sheet of the invention can be generally transparent and/visually clear. The term “visually clear” is defined herein as an appreciable absence of cloudiness, haziness, and/or muddiness, when inspected visually. In another embodiment, when the polyesters are blended with polycarbonate, including but not limited to, bisphenol A polycarbonates, the blends can be visually clear.

In other embodiments of the invention, the polyesters useful in the film or sheet of the invention may have a yellowness index (ASTM D-1925) of less than 50 or less than 20.

In one embodiment, the polyesters useful in the film or sheet of the invention and/or the polyester compositions of the invention, with or without toners, can have color values L*, a* and b* which can be determined using a Hunter Lab Ultrascan Spectra Colorimeter manufactured by Hunter Associates Lab Inc., Reston, Va. The color determinations are averages of values measured on either pellets of the polyesters or plaques or other items injection molded or extruded from them. They are determined by the L*a*b* color system of the CIE (International Commission on Illumination) (translated), wherein L* represents the lightness coordinate, a* represents the red/green coordinate, and b* represents the yellow/blue coordinate. In certain embodiments, the b* values for the polyesters useful in the film or sheet of the invention can be from −10 to less than 10 and the L* values can be from 50 to 90. In other embodiments, the b* values for the polyesters useful in the film or sheet of the invention can be present in one of the following ranges: from: from −10 to 9; −10 to 8; −10 to 7; −10 to 6; −10 to 5; −10 to 4; −10 to 3; −10 to 2; from −5 to 9; −5 to 8; −5 to 7; −5 to 6; −5 to 5; −5 to 4; −5 to 3; −5 to 2; 0 to 9; 0 to 8; 0 to 7; 0 to 6; 0 to 5; 0 to 4; 0 to 3; 0 to 2; 1 to 10; 1 to 9; 1 to 8; 1 to 7; 1 to 6; 1 to 5; 1 to 4; 1 to 3; and 1 to 2. In other embodiments, the L* value for the polyesters useful in the film or sheet of the invention can be present in one of the following ranges: 50 to 60; 50 to 70; 50 to 80; 50 to 90; 60 to 70; 60 to 80; 60 to 90; 70 to 80; 79 to 90.

In some embodiments, use of the polyester compositions useful in film or sheet of the invention minimizes and/or eliminates the drying step prior to melt processing and/or thermoforming.

The polyester portion of the polyester compositions useful in the film or sheet of invention can be made by processes known from the literature such as, for example, by processes in homogenous solution, by transesterification processes in the melt, and by two phase interfacial processes. Suitable methods include, but are not limited to, the steps of reacting one or more dicarboxylic acids with one or more glycols at a temperature of 100° C. to 315° C. at a pressure of 0.1 to 760 mm Hg for a time sufficient to form a polyester. See U.S. Pat. No. 3,772,405 for methods of producing polyesters, the disclosure regarding such methods is hereby incorporated herein by reference.

In another aspect, the invention relates to a process for producing a polyester useful in the film or sheet of the invention. The process comprises:

(I) heating a mixture comprising the monomers useful in any of the polyesters useful in the film or sheet of the invention in the presence of a catalyst at a temperature of 150 to 240° C. for a time sufficient to produce an initial polyester;

(II) heating the initial polyester of step (I) at a temperature of 240 to 320° C. for 1 to 4 hours; and

(III) removing any unreacted glycols.

Suitable catalysts for use in this process include, but are not limited to, organo-zinc or tin compounds. The use of this type of catalyst is well known in the art. Examples of catalysts useful in the present invention include, but are not limited to, zinc acetate, butyltin tris-2-ethylhexanoate, dibutyltin diacetate, and/or dibutyltin oxide. Other catalysts may include, but are not limited to, those based on titanium, zinc, manganese, lithium, germanium, and cobalt. Catalyst amounts can range from 10 ppm to 20,000 ppm or 10 to 10,000 ppm, or 10 to 5000 ppm or 10 to 1000 ppm or 10 to 500 ppm, or 10 to 300 ppm or 10 to 250 based on the catalyst metal and based on the weight of the final polymer. The process can be carried out in either a batch or continuous process.

Typically, step (I) can be carried out until 50% by weight or more of the 2,2,4,4-tetramethyl-1,3-cyclobutanediol has been reacted. Step (I) may be carried out under pressure, ranging from atmospheric pressure to 100 psig. The term “reaction product” as used in connection with any of the catalysts useful in the invention refers to any product of a polycondensation or esterification reaction with the catalyst and any of the monomers used in making the polyester as well as the product of a polycondensation or esterification reaction between the catalyst and any other type of additive.

Typically, Step (II) and Step (III) can be conducted at the same time. These steps can be carried out by methods known in the art such as by placing the reaction mixture under a pressure ranging from 0.002 psig to below atmospheric pressure, or by blowing hot nitrogen gas over the mixture.

The invention further relates to a polyester product useful in the film or sheet of the invention made by the process described above.

The invention further relates to film or sheet comprising a polymer blend. The blend comprises:

(a) 5 to 95 wt % of at least one of the polyesters described above; and

(b) 5 to 95 wt % of at least one of the polymeric components.

Suitable examples of the polymeric components include, but are not limited to, nylon; polyesters different from those described herein; polyamides such as ZYTEL® from DuPont; polystyrene; polystyrene copolymers; styrene acrylonitrile copolymers; acrylonitrile butadiene styrene copolymers; poly(methylmethacrylate); acrylic copolymers; poly(ether-imides) such as ULTEM® (a poly(ether-imide) from General Electric); polyphenylene oxides such as poly(2,6-dimethylphenylene oxide) or poly(phenylene oxide)/polystyrene blends such as NORYL 1000® (a blend of poly(2,6-dimethylphenylene oxide) and polystyrene resins from General Electric); polyphenylene sulfides; polyphenylene sulfide/sulfones; poly(ester-carbonates); polycarbonates such as LEXAN® (a polycarbonate from General Electric); polysulfones; polysulfone ethers; and poly(ether-ketones) of aromatic dihydroxy compounds or mixtures of any of the foregoing polymers. The blends can be prepared by conventional processing techniques known in the art, such as melt blending or solution blending. In one embodiment, polycarbonate is not present in the polyester composition useful in the invention. If polycarbonate is used in a blend in the polyester compositions useful in the invention, the blends can be visually clear. However, the polyester compositions useful in the film or sheet of the invention also contemplate the exclusion of polycarbonate as well as the inclusion of polycarbonate.

Polycarbonates useful in the film or sheet of the invention may be prepared according to known procedures, for example, by reacting the dihydroxyaromatic compound with a carbonate precursor such as phosgene, a haloformate or a carbonate ester, a molecular weight regulator, an acid acceptor and a catalyst. Methods for preparing polycarbonates are known in the art and are described, for example, in U.S. Pat. No. 4,452,933, where the disclosure regarding the preparation of polycarbonates is hereby incorporated by reference herein.

Examples of suitable carbonate precursors include, but are not limited to, carbonyl bromide, carbonyl chloride, or mixtures thereof; diphenyl carbonate; a di(halophenyl)carbonate, e.g., di(trichlorophenyl)carbonate, di(tribromophenyl)carbonate, and the like; di(alkylphenyl)carbonate, e.g., di(tolyl)carbonate; di(naphthyl)carbonate; di(chloronaphthyl)carbonate, or mixtures thereof; and bis-haloformates of dihydric phenols.

Examples of suitable molecular weight regulators include, but are not limited to, phenol, cyclohexanol, methanol, alkylated phenols, such as octylphenol, para-tertiary-butyl-phenol, and the like. In one embodiment, the molecular weight regulator is phenol or an alkylated phenol.

The acid acceptor may be either an organic or an inorganic acid acceptor. A suitable organic acid acceptor can be a tertiary amine and includes, but is not limited to, such materials as pyridine, triethylamine, dimethylaniline, tributylamine, and the like. The inorganic acid acceptor can be either a hydroxide, a carbonate, a bicarbonate, or a phosphate of an alkali or alkaline earth metal.

The catalysts that can be used include, but are not limited to, those that typically aid the polymerization of the monomer with phosgene. Suitable catalysts include, but are not limited to, tertiary amines such as triethylamine, tripropylamine, N,N-dimethylaniline, quaternary ammonium compounds such as, for example, tetraethylammonium bromide, cetyl triethyl ammonium bromide, tetra-n-heptylammonium iodide, tetra-n-propyl ammonium bromide, tetramethyl ammonium chloride, tetra-methyl ammonium hydroxide, tetra-n-butyl ammonium iodide, benzyltrimethyl ammonium chloride and quaternary phosphonium compounds such as, for example, n-butyltriphenyl phosphonium bromide and methyltriphenyl phosphonium bromide.

The polycarbonates useful in the polyester compositions useful in the film or sheet of the invention also may be copolyestercarbonates such as those described in U.S. Pat. Nos. 3,169,121; 3,207,814; 4,194,038; 4,156,069; 4,430,484, 4,465,820, and 4,981,898, where the disclosure regarding copolyestercarbonates from each of the U.S. patents is incorporated by reference herein.

Copolyestercarbonates useful in the film or sheet of this invention can be available commercially and/or may be prepared by known methods in the art. For example, they can be typically obtained by the reaction of at least one dihydroxyaromatic compound with a mixture of phosgene and at least one dicarboxylic acid chloride, especially isophthaloyl chloride, terephthaloyl chloride, or both.

In addition, the polyester compositions and the polymer blend compositions containing the polyesters useful in the film or sheet of this invention may also contain from 0.01 to 25% by weight or 0.01 to 20% by weight or 0.01 to 15% by weight or 0.01 to 10% by weight or 0.01 to 5% by weight of the total weight of the polyester composition of common additives such as colorants, dyes, mold release agents, flame retardants, plasticizers, nucleating agents, stabilizers, including but not limited to, UV stabilizers, thermal stabilizers and/or thereof, fillers, and impact modifiers. For example, UV additives can be incorporated into the articles of manufacture of the invention through addition to the bulk, through application of a hard coat, or through the coextrusion of a cap layer. Examples of typical commercially available impact modifiers well known in the art and useful in this invention include, but are not limited to, ethylene/propylene terpolymers; functionalized polyolefins, such as those containing methyl acrylate and/or glycidyl methacrylate; styrene-based block copolymeric impact modifiers; and various acrylic core/shell type impact modifiers. Residues of such additives are also contemplated as part of the polyester composition.

The polyesters useful in the film or sheet of the invention can comprise at least one chain extender. Suitable chain extenders include, but are not limited to, multifunctional (including, but not limited to, bifunctional) isocyanates, multifunctional epoxides, including for example, epoxylated novolacs, and phenoxy resins. In certain embodiments, chain extenders may be added at the end of the polymerization process or after the polymerization process. If added after the polymerization process, chain extenders can be incorporated by compounding or by addition during conversion processes such as injection molding or extrusion. The amount of chain extender used can vary depending on the specific monomer composition used and the physical properties desired but is generally about 0.1 percent by weight to about 10 percent by weight, preferably about 0.1 to about 5 percent by weight, based on the total weight of the polyester.

Thermal stabilizers are compounds that stabilize polyesters during polyester manufacture and/or post polymerization, including but not limited to phosphorous compounds including but not limited to phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphonous acid, and various esters and salts thereof. These can be present in the polyester compositions useful in the film or sheet of the invention. The esters can be alkyl, branched alkyl, substituted alkyl, difunctional alkyl, alkyl ethers, aryl, and substituted aryl. In one embodiment, the number of ester groups present in the particular phosphorous compound can vary from zero up to the maximum allowable based on the number of hydroxyl groups present on the thermal stabilizer used. The term “thermal stabilizer” is intended to include the reaction product(s) thereof. The term “reaction product” as used in connection with the thermal stabilizers of the invention refers to any product of a polycondensation or esterification reaction between the thermal stabilizer and any of the monomers used in making the polyester as well as the product of a polycondensation or esterification reaction between the catalyst and any other type of additive.

Reinforcing materials may be useful in the compositions useful in the film or sheet of this invention. The reinforcing materials may include, but are not limited to, carbon filaments, silicates, mica, clay, talc, titanium dioxide, Wollastonite, glass flakes, glass beads and fibers, and polymeric fibers and combinations thereof. In one embodiment, the reinforcing materials are glass, such as fibrous glass filaments, mixtures of glass and talc, glass and mica, and glass and polymeric fibers.

In another embodiment, the invention further relates to articles of manufacture comprising at least one film or sheet comprising any of polyesters and blends described above.

In another embodiment, the invention further relates to articles of manufacture comprising the film(s) and/or sheet(s) containing any of the polyester compositions described herein.

The films and/or sheets useful in the film or sheet of the present invention can be of any thickness which would be apparent to one of ordinary skill in the art. In one embodiment, the sheet(s) of the invention have a thickness of greater than 40 mils. In one embodiment, the film(s) of the invention have a thickness of less than 40 mils.

Examples of film(s) and/or sheet(s) of the invention include but not limited to extruded film(s) and/or sheet(s), calendered film(s) and/or sheet(s), compression molded film(s) and/or sheet(s), solution casted film(s) and/or sheet(s). The methods of forming polyesters into film(s) and/or sheet(s) are well known in the art. Methods of making film and/or sheet include but are not limited to extrusion, calendering, compression molding, and solution casting.

Examples of potential articles made from film and/or sheet include, but are not limited, to uniaxially stretched film, biaxially stretched film, shrink film (whether or not uniaxially or biaxially stretched, liquid crystal display film (including but not limited to diffuser sheets, compensation films and protective films), thermoformed sheet, graphic arts film, outdoor signs, skylights, coated articles, painted articles, laminates, laminated articles, and/or multiwall films or sheets.

Examples of graphic arts film include, but are not limited to, nameplates, membrane switch overlays; point-of-purchase displays; flat or in-mold decorative panels on washing machines; flat touch panels on refrigerators; flat panel on ovens; decorative interior trim for automobiles; instrument clusters for automobiles; cell phone covers; heating and ventilation control displays; automotive console panels; automotive gear shift panels; control displays or warning signals for automotive instrument panels; facings, dials or displays on household appliances; facings, dials or displays on washing machines; facings, dials or displays on dishwashers; keypads for electronic devices; keypads for mobile phones, PDAs (hand-held computers) or remote controls; displays for electronic devices; displays for hand-held electronic devices such as phones and PDAs; panels and housings for mobile or standard phones; logos on electronic devices; and logos for hand-held phones.

Multiwall film or sheet refers to sheet extruded as a profile consisting of multiple layers that are connected to each other by means of vertical ribs. Examples of multiwall film or sheet include but are not limited to greenhouses and commercial canopies.

Examples of extruded articles include but are not limited to film for graphic arts, applications, outdoor signs, skylights, film for plastic glass laminates, and liquid crystal display (LCD) films, including, but not limited to, diffuser sheets, compensation films, and protective films.

As used herein, the abbreviation “wt” means “weight”.

The following examples further illustrate how the polyester compositions of the invention can be made and evaluated, and are intended to be purely exemplary of the invention and are not intended to limit the scope thereof. Unless indicated otherwise, parts are parts by weight, temperature is in degrees C. or is at room temperature, and pressure is at or near atmospheric.

EXAMPLES

Measurement Methods

The inherent viscosity of the polyesters was determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.

Unless stated otherwise, the glass transition temperature (T_(g)) was determined using a TA DSC 2920 instrument from Thermal Analyst Instruments at a scan rate of 20° C./min according to ASTM D3418.

The glycol content and the cis/trans ratio of the compositions were determined by proton nuclear magnetic resonance (NMR) spectroscopy. All NMR spectra were recorded on a JEOL Eclipse Plus 600 MHz nuclear magnetic resonance spectrometer using either chloroform-trifluoroacetic acid (70-30 volume/volume) for polymers or, for oligomeric samples, 60/40 (wt/wt) phenol/tetrachloroethane with deuterated chloroform added for lock. Peak assignments for 2,2,4,4-tetramethyl-1,3-cyclobutanediol resonances were made by comparison to model mono- and dibenzoate esters of 2,2,4,4-tetramethyl-1,3-cyclobutanediol. These model compounds closely approximate the resonance positions found in the polymers and oligomers.

The crystallization half-time, t½, was determined by measuring the light transmission of a sample via a laser and photo detector as a function of time on a temperature controlled hot stage. This measurement was done by exposing the polymers to a temperature, T_(max), and then cooling it to the desired temperature. The sample was then held at the desired temperature by a hot stage while transmission measurements were made as a function of time. Initially, the sample was visually clear with high light transmission and became opaque as the sample crystallized. The crystallization half-time was recorded as the time at which the light transmission was halfway between the initial transmission and the final transmission. T_(max) is defined as the temperature required to melt the crystalline domains of the sample (if crystalline domains are present). The T_(max) reported in the examples below represents the temperature at which each sample was heated to condition the sample prior to crystallization half time measurement. The T_(max) temperature is dependant on composition and is typically different for each polyester. For example, PCT may need to be heated to some temperature greater than 290° C. to melt the crystalline domains.

Density was determined using a gradient density column at 23° C.

The melt viscosity reported herein was measured by using a Rheometrics Dynamic Analyzer (RDA II). The melt viscosity was measured as a function of shear rate, at frequencies ranging from 1 to 400 rad/sec, at the temperatures reported. The zero shear melt viscosity (η_(o)) is the melt viscosity at zero shear rate estimated by extrapolating the data by known models in the art. This step is automatically performed by the Rheometrics Dynamic Analyzer (RDA II) software.

The polymers were dried at a temperature ranging from 80 to 100° C. in a vacuum oven for 24 hours and injection molded on a Boy 22S molding machine to give ⅛×½×5-inch and ¼×½×5-inch flexure bars. These bars were cut to a length of 2.5 inch and notched down the ½ inch width with a 10-mil notch in accordance with ASTM D256. The average Izod impact strength at 23° C. was determined from measurements on 5 specimens.

In addition, 5 specimens were tested at various temperatures using 5° C. increments in order to determine the brittle-to-ductile transition temperature. The brittle-to-ductile transition temperature is defined as the temperature at which 50% of the specimens fail in a brittle manner as denoted by ASTM D256.

Color values reported herein were determined using a Hunter Lab Ultrascan Spectra Colorimeter manufactured by Hunter Associates Lab Inc., Reston, Va. The color determinations were averages of values measured on either pellets of the polyesters or plaques or other items injection molded or extruded from them. They were determined by the L*a*b* color system of the CIE (International Commission on Illumination) (translated), wherein L* represents the lightness coordinate, a* represents the red/green coordinate, and b* represents the yellow/blue coordinate.

In addition, 10-mil films were compression molded using a Carver press at 240° C.

Unless otherwise specified, the cis/trans ratio of the 1,4 cyclohexanedimethanol used in the following examples was approximately 30/70, and could range from 35/65 to 25/75. Unless otherwise specified, the cis/trans ratio of the 2,2,4,4-tetramethyl-1,3-cyclobutanediol used in the following examples was approximately 50/50.

The following abbreviations apply throughout the working examples and figures: TPA Terephthalic acid DMT Dimethyl terephthalate TMCD 2,2,4,4-tetramethyl-1,3-cyclobutanediol CHDM 1,4-cyclohexanedimethanol IV Inherent viscosity η_(o) Zero shear melt viscosity T_(g) Glass transition temperature T_(bd) Brittle-to-ductile transition temperature T_(max) Conditioning temperature for crystallization half time measurements

Example 1

This example illustrates that 2,2,4,4-tetramethyl-1,3-cyclobutanediol is more effective at reducing the crystallization rate of PCT than ethylene glycol or isophthalic acid. In addition, this example illustrates the benefits of 2,2,4,4-tetramethyl-1,3-cyclobutanediol on the glass transition temperature and density.

A variety of copolyesters were prepared as described below. These copolyesters were all made with 200 ppm dibutyl tin oxide as the catalyst in order to minimize the effect of catalyst type and concentration on nucleation during crystallization studies. The cis/trans ratio of the 1,4-cyclohexanedimethanol was 31/69 while the cis/trans ratio of the 2,2,4,4-tetramethyl-1,3-cyclobutanediol is reported in Table 1.

For purposes of this example, the samples had sufficiently similar inherent viscosities thereby effectively eliminating this as a variable in the crystallization rate measurements.

Crystallization half-time measurements from the melt were made at temperatures from 140 to 200° C. at 10° C. increments and are reported in Table 1. The fastest crystallization half-time for each sample was taken as the minimum value of crystallization half-time as a function of temperature, typically occurring around 170 to 180° C. The fastest crystallization half-times for the samples are plotted in FIG. 1 as a function of mole % comonomer modification to PCT.

The data shows that 2,2,4,4-tetramethyl-1,3-cyclobutanediol is more effective than ethylene glycol and isophthalic acid at decreasing the crystallization rate (i.e., increasing the crystallization half-time). In addition, 2,2,4,4-tetramethyl-1,3-cyclobutanediol increases T_(g) and lowers density. TABLE 1 Crystallization Half-times (min) at at at at at at at Comonomer IV Density T_(g) T_(max) 140° C. 150° C. 160° C. 170° C. 180° C. 190° C. 200° C. Example (mol %)¹ (dl/g) (g/ml) (° C.) (° C.) (min) (min) (min) (min) (min) (min) (min) 1A 20.2% A² 0.630 1.198 87.5 290 2.7 2.1 1.3 1.2 0.9 1.1 1.5 1B 19.8% B 0.713 1.219 87.7 290 2.3 2.5 1.7 1.4 1.3 1.4 1.7 1C 20.0% C 0.731 1.188 100.5 290 >180 >60 35.0 23.3 21.7 23.3 25.2 1D 40.2% A² 0.674 1.198 81.2 260 18.7 20.0 21.3 25.0 34.0 59.9 96.1 1E 34.5% B 0.644 1.234 82.1 260 8.5 8.2 7.3 7.3 8.3 10.0 11.4 1F 40.1% C 0.653 1.172 122.0 260 >10 days >5 days >5 days 19204 >5 days >5 days >5 days 1G 14.3% D 0.646³ 1.188 103.0 290 55.0 28.8 11.6 6.8 4.8 5.0 5.5 1H 15.0% E 0.728⁴ 1.189 99.0 290 25.4 17.1 8.1 5.9 4.3 2.7 5.1 ¹The balance of the diol component of the polyesters in Table 1 is 1,4-cyclohexanedimethanol; and the balance of the dicarboxylic acid component of the polyesters in Table 1 is dimethyl terephthalate; if the dicarboxylic acid is not described, it is 100 mole % dimethyl terephthalate. ²100 mole % 1,4-cyclohexanedimethanol. ³A film was pressed from the ground polyester of Example 1G at 240° C. The resulting film had an inherent viscosity value of 0.575 dL/g. ⁴A film was pressed from the ground polyester of Example 1H at 240° C. The resulting film had an inherent viscosity value of 0.0.652 dL/g. where: A is Isophthalic Acid B is Ethylene Glycol C is 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (approx. 50/50 cis/trans) D is 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (98/2 cis/trans) E is 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (5/95 cis/trans)

As shown in Table 1 and FIG. 1, 2,2,4,4-tetramethyl-1,3-cyclobutanediol is more effective than other comonomers, such ethylene glycol and isophthalic acid, at increasing the crystallization half-time, i.e., the time required for a polymer to reach half of its maximum crystallinity. By decreasing the crystallization rate of PCT (increasing the crystallization half-time), amorphous articles based on 2,2,4,4-tetramethyl-1,3-cyclobutanediol-modified PCT as described herein may be fabricated by methods known in the art. As shown in Table 1, these materials can exhibit higher glass transition temperatures and lower densities than other modified PCT copolyesters.

Preparation of the polyesters shown on Table 1 is described below.

Example 1A

This example illustrates the preparation of a copolyester with a target composition of 80 mol % dimethyl terephthalate residues, 20 mol % dimethyl isophthalate residues, and 100 mol % 1,4-cyclohexanedimethanol residues (28/72 cis/trans).

A mixture of 56.63 g of dimethyl terephthalate, 55.2 g of 1,4-cyclohexanedimethanol, 14.16 g of dimethyl isophthalate, and 0.0419 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 210° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 210° C. for 5 minutes and then the temperature was gradually increased to 290° C. over 30 minutes. The reaction mixture was held at 290° C. for 60 minutes and then vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 5 minutes. A pressure of 0.3 mm of Hg was maintained for a total time of 90 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 87.5° C. and an inherent viscosity of 0.63 dl/g. NMR analysis showed that the polymer was composed of 100 mol % 1,4-cyclohexanedimethanol residues and 20.2 mol % dimethyl isophthalate residues.

Example 1B

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 20 mol % ethylene glycol residues, and 80 mol % 1,4-cyclohexanedimethanol residues (32/68 cis/trans).

A mixture of 77.68 g of dimethyl terephthalate, 50.77 g of 1,4-cyclohexanedimethanol, 27.81 g of ethylene glycol, and 0.0433 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 200° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 200° C. for 60 minutes and then the temperature was gradually increased to 210° C. over 5 minutes. The reaction mixture was held at 210° C. for 120 minutes and then heated up to 280° C. in 30 minutes. Once at 280° C., vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 10 minutes. A pressure of 0.3 mm of Hg was maintained for a total time of 90 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 87.7° C. and an inherent viscosity of 0.71 dl/g. NMR analysis showed that the polymer was composed of 19.8 mol % ethylene glycol residues.

Example 1C

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 20 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and 80 mol % 1,4-cyclohexanedimethanol residues (31/69 cis/trans).

A mixture of 77.68 g of dimethyl terephthalate, 48.46 g of 1,4-cyclohexanedimethanol, 17.86 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.046 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. This polyester was prepared in a manner similar to that described in Example 1A. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 100.5° C. and an inherent viscosity of 0.73 dl/g. NMR analysis showed that the polymer was composed of 80.5 mol % 1,4-cyclohexanedimethanol residues and 19.5 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

Example 1D

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 40 mol % dimethyl isophthalate residues, and 100 mol % 1,4-cyclohexanedimethanol residues (28/72 cis/trans).

A mixture of 42.83 g of dimethyl terephthalate, 55.26 g of 1,4-cyclohexanedimethanol, 28.45 g of dimethyl isophthalate, and 0.0419 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 210° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 210° C. for 5 minutes and then the temperature was gradually increased to 290° C. over 30 minutes. The reaction mixture was held at 290° C. for 60 minutes and then vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 5 minutes. A pressure of 0.3 mm of Hg was maintained for a total time of 90 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 81.2° C. and an inherent viscosity of 0.67 dl/g. NMR analysis showed that the polymer was composed of 100 mol % 1,4-cyclohexanedimethanol residues and 40.2 mol % dimethyl isophthalate residues.

Example 1E

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 40 mol % ethylene glycol residues, and 60 mol % 1,4-cyclohexanedimethanol residues (31/69 cis/trans).

A mixture of 81.3 g of dimethyl terephthalate, 42.85 g of 1,4-cyclohexanedimethanol, 34.44 g of ethylene glycol, and 0.0419 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 200° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 200° C. for 60 minutes and then the temperature was gradually increased to 210° C. over 5 minutes. The reaction mixture was held at 210° C. for 120 minutes and then heated up to 280° C. in 30 minutes. Once at 280° C., vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 10 minutes. A pressure of 0.3 mm of Hg was maintained for a total time of 90 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 82.1° C. and an inherent viscosity of 0.64 dl/g. NMR analysis showed that the polymer was composed of 34.5 mol % ethylene glycol residues.

Example 1F

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 40 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, and 60 mol % 1,4-cyclohexanedimethanol residues (31/69 cis/trans).

A mixture of 77.4 g of dimethyl terephthalate, 36.9 g of 1,4-cyclohexanedimethanol, 32.5 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.046 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 210° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 210° C. for 3 minutes and then the temperature was gradually increased to 260° C. over 30 minutes. The reaction mixture was held at 260° C. for 120 minutes and then heated up to 290° C. in 30 minutes. Once at 290° C., vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 5 minutes. A pressure of 0.3 mm of Hg was maintained for a total time of 90 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 122° C. and an inherent viscosity of 0.65 dl/g. NMR analysis showed that the polymer was composed of 59.9 mol % 1,4-cyclohexanedimethanol residues and 40.1 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

Example 1G

This example illustrates the preparation of a copolyester with a target composition of 100 mol % dimethyl terephthalate residues, 20 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues (98/2 cis/trans), and 80 mol % 1,4-cyclohexanedimethanol residues (31/69 cis/trans).

A mixture of 77.68 g of dimethyl terephthalate, 48.46 g of 1,4-cyclohexanedimethanol, 20.77 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.046 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 210° C. The stirring speed was set to 200 RPM throughout the experiment. The contents of the flask were heated at 210° C. for 3 minutes and then the temperature was gradually increased to 260° C. over 30 minutes. The reaction mixture was held at 260° C. for 120 minutes and then heated up to 290° C. in 30 minutes. Once at 290° C., vacuum was gradually applied over the next 5 minutes until the pressure inside the flask reached 100 mm of Hg and the stirring speed was also reduced to 100 RPM. The pressure inside the flask was further reduced to 0.3 mm of Hg over the next 5 minutes and the stirring speed was reduced to 50 RPM. A pressure of 0.3 mm of Hg was maintained for a total time of 60 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 103° C. and an inherent viscosity of 0.65 dl/g. NMR analysis showed that the polymer was composed of 85.7 mol % 1,4-cyclohexanedimethanol residues and 14.3 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

Example 1H

This example illustrates the preparation of a copolyester with a target composition of 100 mole % dimethyl terephthalate residues, 20 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues (5/95 cis/trans), and 80 mol % 1,4-cyclohexanedimethanol residues (31/69 cis/trans).

A mixture of 77.68 g of dimethyl terephthalate, 48.46 g of 1,4-cyclohexanedimethanol, 20.77 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.046 g of dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 210° C. The stirring speed was set to 200 RPM at the beginning of the experiment. The contents of the flask were heated at 210° C. for 3 minutes and then the temperature was gradually increased to 260° C. over 30 minutes. The reaction mixture was held at 260° C. for 120 minutes and then heated up to 290° C. in 30 minutes. Once at 290° C., vacuum was gradually applied over the next 5 minutes with a set point of 100 mm of Hg and the stirring speed was also reduced to 100 RPM. The pressure inside the flask was further reduced to a set point of 0.3 mm of Hg over the next 5 minutes and the stirring speed was reduced to 50 RPM. This pressure was maintained for a total time of 60 minutes to remove excess unreacted diols. It was noted that the vacuum system failed to reach the set point mentioned above, but produced enough vacuum to produce a high melt viscosity, visually clear and colorless polymer with a glass transition temperature of 99° C. and an inherent viscosity of 0.73 dl/g. NMR analysis showed that the polymer was composed of 85 mol % 1,4-cyclohexanedimethanol residues and 15 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

Example 2

This example illustrates that 2,2,4,4-tetramethyl-1,3-cyclobutanediol improves the toughness of PCT-based copolyesters (polyesters containing terephthalic acid and 1,4-cyclohexanedimethanol).

Copolyesters based on 2,2,4,4-tetramethyl-1,3-cyclobutanediol were prepared as described below. The cis/trans ratio of the 1,4-cyclohexanedimethanol was approximately 31/69 for all samples. Copolyesters based on ethylene glycol and 1,4-cyclohexanedimethanol were commercial polyesters. The copolyester of Example 2A (Eastar PCTG 5445) was obtained from Eastman Chemical Co. The copolyester of Example 2B was obtained from Eastman Chemical Co. under the trade name Spectar. Example 2C and Example 2D were prepared on a pilot plant scale (each a 15-lb batch) following an adaptation of the procedure described in Example 1A and having the inherent viscosities and glass transition temperatures described in Table 2 below. Example 2C was prepared with a target tin amount of 300 ppm (Dibutyltin Oxide). The final product contained 295 ppm tin. The color values for the polyester of Example 2C were L*=77.11; a*=−1.50; and b*=5.79. Example 2D was prepared with a target tin amount of 300 ppm (Dibutyltin Oxide). The final product contained 307 ppm tin. The color values for the polyester of Example 2D were L*=66.72; a*=−1.22; and b*=16.28.

Materials were injection molded into bars and subsequently notched for Izod testing. The notched Izod impact strengths were obtained as a function of temperature and are also reported in Table 2.

For a given sample, the Izod impact strength undergoes a major transition in a short temperature span. For instance, the Izod impact strength of a copolyester based on 38 mol % ethylene glycol undergoes this transition between 15 and 20° C. This transition temperature is associated with a change in failure mode; brittle/low energy failures at lower temperatures and ductile/high energy failures at higher temperatures. The transition temperature is denoted as the brittle-to-ductile transition temperature, T_(bd), and is a measure of toughness. T_(bd) is reported in Table 2 and plotted against mol % comonomer in FIG. 2.

The data shows that adding 2,2,4,4-tetramethyl-1,3-cyclobutanediol to PCT lowers T_(bd) and improves the toughness, as compared to ethylene glycol, which increases T_(bd) of PCT. TABLE 2 Notched Izod Impact Energy (ft-lb/in) Comonomer (mol IV T_(g) T_(bd) at at at at at at at at at at Example %)¹ (dl/g) (° C.) (° C.) −20° C. −15° C. −10° C. −5° C. 0° C. 5° C. 10° C. 15° C. 20° C. 25° C. at 30° C. 2A 38.0% B 0.68 86 18 NA NA NA 1.5 NA NA 1.5 1.5 32 32 NA 2B 69.0% B 0.69 82 26 NA NA NA NA NA NA 2.1 NA 2.4 13.7 28.7 2C 22.0% C 0.66 106 −5 1.5 NA 12 23 23 NA 23 NA NA NA NA 2D 42.8% C 0.60 133 −12 2.5 2.5 11 NA 14 NA NA NA NA NA NA ¹The balance of the glycol component of the polyesters in the Table is 1,4-cyclohexanedimethanol. All polymers were prepared from 100 mole % dimethyl terephthalate. NA = Not available. where: B is Ethylene glycol C is 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (50/50 cis/trans)

Example 3

This example illustrates that 2,2,4,4-tetramethyl-1,3-cyclobutanediol can improve the toughness of PCT-based copolyesters(polyesters containing terephthalic acid and 1,4-cyclohexanedimethanol). Polyesters prepared in this example comprise 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in an amount of 40 mol % or greater.

Copolyesters based on dimethyl terephthalate, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 1,4-cyclohexanedimethanol were prepared as described below, having the composition and properties shown in the table below. The balance up to 100 mol % of the diol component of the polyesters in the table below was 1,4-cyclohexanedimethanol (31/69 cis/trans).

Materials were injection molded into both 3.2 mm and 6.4 mm thick bars and subsequently notched for Izod impact testing. The notched Izod impact strengths were obtained at 23° C. and are reported in the table below. Density, Tg, and crystallization halftime were measured on the molded bars. Melt viscosity was measured on pellets at 290° C. TABLE 3 Compilation of various properties for certain polyesters useful in the invention Notched Notched Izod of Izod of Crystallization Melt 3.2 mm 6.4 mm Halftime Viscosity Molded thick thick from at 1 rad/sec Pellet Bar bars at bars at Specific melt at at TMCD % cis IV IV 23° C. 23° C. Gravity Tg 170° C. 290° C. Example mole % TMCD (dl/g) (dl/g) (J/m) (J/m) (g/mL) (° C.) (min) (Poise) A 44 46.2 0.657 0.626 727 734 1.172 119 NA 9751 B 45 NA 0.626 0.580 748 237 1.167 123 NA 8051 C 45 NA 0.582 0.550 671 262 1.167 125 19782 5835 D 45 NA 0.541 0.493 424 175 1.167 123 NA 3275 E 59 46.6 0.604 0.576 456 311 1.156 139 NA 16537  NA = Not available.

Example 3A

21.24 lb (49.71 gram-mol) dimethyl terephthalate, 8.84 lb (27.88 gram-mol) 1,4-cyclohexanedimethanol, and 10.08 lb (31.77 gram-mol) 2,2,4,4-tetramethyl-1,3-cyclobutanediol were reacted together in the presence of 200 ppm of the catalyst butyltin tris(2-ethylhexanoate). The reaction was carried out under a nitrogen gas purge in an 18-gallon stainless steel pressure vessel fitted with a condensing column, a vacuum system, and a HELICONE-type agitator. With the agitator running at 25 RPM, the reaction mixture temperature was increased to 250° C. and the pressure was increased to 20 psig. The reaction mixture was held for 2 hours at 250° C. and 20 psig pressure. The pressure was then decreased to 0 psig at a rate of 3 psig/minute. Then the agitator speed was decreased to 15 RPM, the temperature of the reaction mixture was then increased to 290° C. and the pressure was decreased to 2 mm of Hg. The reaction mixture was held at 290° C. and at a pressure of 2 mm of Hg until the power draw to the agitator no longer increased (80 minutes). The pressure of the pressure vessel was then increased to 1 atmosphere using nitrogen gas. The molten polymer was then extruded from the pressure vessel. The cooled, extruded polymer was ground to pass a 6-mm screen. The polymer had an inherent viscosity of 0.657 dL/g and a Tg of 119° C. NMR analysis showed that the polymer was composed of 56.3 mol % 1,4-cyclohexane-dimethanol residues and 43.7 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues. The polymer had color values of: L*=75.04, a*=−1.82, and b*=6.72.

Example 3B to Example 3D

The polyesters described in Example 3B to Example 3D were prepared following a procedure similar to the one described for Example 3A. The composition and properties of these polyesters are shown in the table below.

Example 3E

21.24 lb (49.71 gram-mol) dimethyl terephthalate, 6.43 lb (20.28 gram-mol 1,4-cyclohexanedimethanol, and 12.49 lb (39.37 gram-mol) 2,2,4,4-tetramethyl-1,3-cyclobutanediol were reacted together in the presence of 200 ppm of the catalyst butyltin tris(2-ethylhexanoate). The reaction was carried out under a nitrogen gas purge in an 18-gallon stainless steel pressure vessel fitted with a condensing column, a vacuum system, and a HELICONE-type agitator. With the agitator running at 25 RPM, the reaction mixture temperature was increased to 250° C. and the pressure was increased to 20 psig. The reaction mixture was held for 2 hours at 250° C. and 20 psig pressure. The pressure was then decreased to 0 psig at a rate of 3 psig/minute. Then the agitator speed was decreased to 15 RPM, the temperature of the reaction mixture was then increased to 290° C. and the pressure was decreased to 2 mm of Hg. The reaction mixture was held at 290° C. and at a pressure of <1 mm of Hg until the power draw to the agitator no longer increased (50 minutes). The pressure of the pressure vessel was then increased to 1 atmosphere using nitrogen gas. The molten polymer was then extruded from the pressure vessel. The cooled, extruded polymer was ground to pass a 6-mm screen. The polymer had an inherent viscosity of 0.604 dL/g and a Tg of 139° C.

NMR analysis showed that the polymer was composed of 40.8 mol % 1,4-cyclohexanedimethanol residues and 59.2 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues. The polymer had color values of: L*=80.48, a*=−1.30, and b*=6.82.

Example 4 Comparative Example

This example shows data for comparative materials are shown in Table 4. The PC was Makrolon 2608 from Bayer, with a nominal composition of 100 mole % bisphenol A residues and 100 mole % diphenyl carbonate residues. Makrolon 2608 has a nominal melt flow rate of 20 grams/10 minutes measured at 300 C using a 1.2 kg weight. The PET was Eastar 9921 from Eastman Chemical Company, with a nominal composition of 100 mole % terephthalic acid, 3.5 mole % cyclohexanedimenthanol (CHDM) and 96.5 mole % ethylene glycol. The PETG was Eastar 6763 from Eastman Chemical Company, with a nominal composition of 100 mole % terephthalic acid, 31 mole % cyclohexanedimenthanol (CHDM) and 69 mole % ethylene glycol. The PCTG was Eastar DNO001 from Eastman Chemical Company, with a nominal composition of 100 mole % terephthalic acid, 62 mole % cyclohexanedimenthanol (CHDM) and 38 mole % ethylene glycol. The PCTA was Eastar AN001 from Eastman Chemical Company, with a nominal composition of 65 mole % terephthalic acid, 35 mole % isophthalic acid and 100 mole % cyclohexanedimenthanol (CHDM). The Polysulfone was Udel 1700 from Solvay, with a nominal composition of 100 mole % bisphenol A residues and 100 mole % 4,4-dichlorosulfonyl sulfone residues. Udel 1700 has a nominal melt flow rate of 6.5 grams/10 minutes measured at 343 C using a 2.16 kg weight. The SAN was Lustran 31 from Lanxess, with a nominal composition of 76 weight % styrene and 24 weight % acrylonitrile. Lustran 31 has a nominal melt flow rate of 7.5 grams/10 minutes measured at 230 C using a 3.8 kg weight. The examples of the invention show improved toughness in 6.4 mm thickness bars compared to all of the other resins. TABLE 4 Compilation of various properties for certain commercial polymers Notched Notched Izod of Izod of 3.2 mm 6.4 mm Crystallization Pellet Molded Bar thick bars thick bars Specific Halftime from Polymer IV IV at 23° C. at 23° C. Gravity Tg melt Example name (dl/g) (dl/g) (J/m) (J/m) (g/mL) (° C.) (min) A PC  12 MFR NA 929  108  1.20 146 NA B PCTG 0.73 0.696 NB 70 1.23 87  30 at 170° C. C PCTA 0.72 0.702 98 59 1.20 87  15 at 150° C. D PETG 0.75 0.692 83 59 1.27 80 2500 at 130° C. E PET 0.76 0.726 45 48 1.33 78   1.5 at 170° C. F SAN 7.5 MFR NA 21 NA 1.07 ˜110 NA G PSU 6.5 MFR NA 69 NA 1.24 ˜190 NA NA = Not available

Example 5

This example illustrates the effect of the amount of 2,2,4,4-tetramethyl-1,3-cyclobutanediol used for the preparation of the polyesters of the invention on the glass transition temperature of the polyesters. Polyesters prepared in this example comprise 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues in an amount of 40 mol % or greater.

Examples A to Z

These polyesters were prepared by carrying out the ester exchange and polycondensation reactions in separate stages. The ester exchange experiments were conducted in a continuous temperature rise (CTR) reactor. The CTR was a 3000 ml glass reactor equipped with a single shaft impeller blade agitator, covered with an electric heating mantle and fitted with a heated packed reflux condenser column. The reactor was charged with 777 g of dimethyl terephthalate, 375 g of 2,2,4,4-tetramethyl-1,3,-cyclobutanediol, 317 g of cyclohexane dimethanol and 1.12 g of butyltin tris-2-ethylhexanoate (such that there will be 200 ppm tin metal in the final polymer). The heating mantle was set manually to 100% output. The set points and data collection were facilitated by a Camile process control system. Once the reactants were melted, stirring was initiated and slowly increased to 250 rpm. The temperature of the reactor gradually increased with run time. The weight of methanol collected was recorded via balance. The reaction was stopped when methanol evolution stopped or at a pre-selected lower temperature of 260° C. The oligomer was discharged with a nitrogen purge and cooled to room temperature. The oligomer was frozen with liquid nitrogen and broken into pieces small enough to be weighed into a 500 ml round bottom flask.

In the polycondensation reactions, a 500 ml round bottom flask was charged with 150 g of the oligomer prepared above. The flask was equipped with a stainless steel stirrer and polymer head. The glassware was set up on a half mole polymer rig and the Camile sequence was initiated. The stirrer was positioned one full turn from the flask bottom once the oligomer melted. The temperature/pressure/stir rate sequence controlled by the Camile software for these examples is reported in the following table, unless otherwise specified below. Camile Sequence for Polycondensation Reactions Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 290 90 50 6 5 290 6 25 7 110 290 6 25

Camile Sequence for Examples O, U, Y, Z Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 290 90 50 6 5 290 6 25 7 110 290 6 25

For Examples A and C the same sequence in the preceding table was used, except the time was 80 min in Stage 7. For Examples D and G, the same sequence in the preceding table was used, except the time was 50 min in Stage 7. For Example I, the same sequence in the preceding table was used, except the time was 140 min Stage 7. Camile Sequence for Example B Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 300 90 50 6 5 300 7 25 7 110 300 7 25

For Example F, the same sequence in the preceding table was used, except the vacuum was 8 torr in Stages 6 and 7. For Example L, the same sequence in the preceding table was used, except the vacuum was 6 torr in Stages 6 and 7. For Example M, the same sequence in the preceding table was used, except the vacuum was 4 torr in Stages 6 and 7. For Example N, the same sequence in the preceding table was used, except the vacuum was 5 torr in Stages 6 and 7. Camile Sequence for Example E Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 280 90 50 6 5 280 5 25 7 110 280 5 25

For Example R and X, the same sequence in the preceding table was used, except the vacuum was 6 torr in Stages 6 and 7. For Example S and T, the same sequence in the preceding table was used, except the vacuum was 6 torr and stir rate was 15 rpm in Stages 6 and 7. For Example V, the same sequence in the preceding table was used, except the stir rate was 15 rpm in Stages 6 and 7. Camile Sequence for Example H Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 300 90 50 6 5 300 6 15 7 110 300 6 15

For Example J, the same sequence in the preceding table was used, except the vacuum was 8 torr in Stages 6 and 7. For Example K, the same sequence in the preceding table was used, except the vacuum was 7 torr in Stages 6 and 7. Camile Sequence for Examples P and Q Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 5 290 6 25 5 110 290 6 25

The resulting polymers were recovered from the flask, chopped using a hydraulic chopper, and ground to a 6 mm screen size. Samples of each ground polymer were submitted for inherent viscosity in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C., catalyst level (Sn) by x-ray fluorescence, and color (L*, a*, b*) by transmission spectroscopy. Polymer composition was obtained by 1H NMR. Samples were submitted for thermal stability and melt viscosity testing using a Rheometrics Mechanical Spectrometer (RMS-800).

Examples AA to AH

The polyesters of these examples were prepared as described above for Examples A to Z, except that the target tin amount in the final polymer was 150 ppm for examples AA to AH. The following tables describe the temperature/pressure/stir rate sequences controlled by the Camile software for these examples. Camile Sequence for Examples AA, AC, and AE Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 400 50 5 110 290 400 50 6 5 290 8 50 7 110 295 8 50

For Example AA, the stirrer was turned to 25 rpm with 95 min left in Stage 7. Camile Sequence for Example AB Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 10 245 760 0 2 5 245 760 50 3 30 283 760 50 4 3 283 175 50 5 5 283 5 50 6 5 283 1.2 50 7 71 285 1.2 50

For Example AH, the same sequence in the preceding table was used, except the time was 75 min in Stage 7. Camile Sequence for Example AD Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 10 245 760 0 2 5 245 760 50 3 30 285 760 50 4 3 285 175 50 5 5 285 5 50 6 5 285 4 50 7 220 290 4 50

Camile Sequence for Example AF Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 285 90 50 6 5 285 6 50 7 70 290 6 50

Camile Sequence for Example AG Time Temp Vacuum Stir Stage (min) (° C.) (torr) (rpm) 1 5 245 760 0 2 5 245 760 50 3 30 265 760 50 4 3 265 90 50 5 110 290 90 50 6 5 290 6 25 7 110 295 6 25

Example AI to AK

Dimethyl terephthalate, 1,4-cyclohexanedimethanol, and 2,2,4,4 tetramethyl-1,3-cyclobutanediol were weighed into a 500-ml single neck round bottom flask. The polyesters of this example were prepared with a 1.2/1 glycol/acid ratio with the entire excess coming from the 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Enough dibutyltin oxide catalyst was added to give 300 ppm tin in the final polymer. The flask was under a 0.2 SCFC nitrogen purge with vacuum reduction capability. The flask was immersed in a Belmont metal bath at 200° C. and stirred at 200 RPM after the reactants had melted. After about 2.5 hours, the temperature was raised to 210° C. and these conditions were held for an additional 2 hours. The temperature was raised to 285° C. (in approximately 25 minutes) and the pressure was reduced to 0.3 mm of Hg over a period of 5 minutes. The stirring was reduced as the viscosity increased, with 15 RPM being the minimum stirring used. The total polymerization time was varied to attain the target inherent viscosities. After the polymerization was complete, the Belmont metal bath was lowered and the polymer was allowed to cool to below its glass transition temperature. After about 30 minutes, the flask was reimmersed in the Belmont metal bath (the temperature had been increased to 295° C. during this 30 minute wait) and the polymer mass was heated until it pulled away from the glass flask. The polymer mass was stirred at mid level in the flask until the polymer had cooled. The polymer was removed from the flask and ground to pass a 3 mm screen. Variations to this procedure were made to produce the copolyesters described below with a targeted composition of 45 mol %.

Inherent viscosities were measured as described in the “Measurement Methods” section above. The compositions of the polyesters were determined by ¹H NMR as explained before in the Measurement Methods section. The glass transition temperatures were determined by DSC, using the second heat after quench at a rate of 20° C./min.

The table below shows the experimental data for the polyesters of this example. The data shows that an increase in the level of 2,2,4,4-tetramethyl-1,3-cyclobutanediol raises the glass transition temperature in an almost linear fashion, for a constant inherent viscosity. FIG. 3 also shows the dependence of Tg on composition and inherent viscosity. TABLE 5 Glass transition temperature as a function of inherent viscosity and composition η_(o) at η_(o) at η_(o) at Ex- mol % % cis IV T_(g) 260° C. 275° C. 290° C. ample TMCD TMCD (dL/g) (° C.) (Poise) (Poise) (Poise) A 44.3 36.3 0.51 119 NA NA NA B 46.1 46.8 0.51 125 NA NA NA C 43.6 72.1 0.52 128 NA NA NA D 43.6 72.3 0.54 127 NA NA NA E 46.4 46.4 0.54 127 NA NA NA F 45.7 47.1 0.55 125 NA NA NA G 44.4 35.6 0.55 118 NA NA NA H 45.2 46.8 0.56 124 NA NA NA I 43.8 72.2 0.56 129 NA NA NA J 45.8 46.4 0.56 124 NA NA NA K 45.1 47.0 0.57 125 NA NA NA L 45.2 46.8 0.57 124 NA NA NA M 45 46.7 0.57 125 NA NA NA N 45.1 47.1 0.58 127 NA NA NA O 44.7 35.4 0.59 123 NA NA NA P 46.1 46.4 0.60 127 NA NA NA Q 45.7 46.8 0.60 129 NA NA NA R 46 46.3 0.62 128 NA NA NA S 45.9 46.3 0.62 128 NA NA NA T 45.8 46.1 0.63 128 NA NA NA U 45.6 50.7 0.63 128 NA NA NA V 46.2 46.8 0.65 129 NA NA NA X 45.9 46.2 0.66 128 NA NA NA Y 45.2 46.4 0.66 128 NA NA NA Z 45.1 46.5 0.68 129 NA NA NA AA 46.3 52.4 0.52 NA NA NA NA AB 45.7 50.9 0.54 NA NA NA NA AC 46.3 52.6 0.56 NA NA NA NA AD 46 50.6 0.56 NA NA NA NA AE 46.5 51.8 0.57 NA NA NA NA AF 45.6 51.2 0.58 NA NA NA NA AG 46 51.9 0.58 NA NA NA NA AH 45.5 51.2 0.59 NA NA NA NA AI 45.8 50.1 0.624 125 NA NA 7696 AJ 45.7 49.4 0.619 128 NA NA 7209 AK 46.2 49.3 0.548 124 NA NA 2348 NA = Not available

Example 6

This example illustrates the effect of the predominance of the type of 2,2,4,4-tetramethyl-1,3-cyclobutanediol isomer (cis or trans) on the glass transition temperature of the polyester.

Dimethyl terephthalate, 1,4-cyclohexanedimethanol, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol were weighed into a 500-ml single neck round bottom flask. The polyesters of this example were prepared with a 1.2/1 glycol/acid ratio with the entire excess coming from the 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Enough dibutyltin oxide catalyst was added to give 300 ppm tin in the final polymer. The flask was under a 0.2 SCFC nitrogen purge with vacuum reduction capability. The flask was immersed in a Belmont metal bath at 200° C. and stirred at 200 RPM after the reactants had melted. After about 2.5 hours, the temperature was raised to 210° C. and these conditions were held for an additional 2 hours. The temperature was raised to 285° C. (in approximately 25 minutes) and the pressure was reduced to 0.3 mm of Hg over a period of 5 minutes. The stirring was reduced as the viscosity increased, with 15 RPM being the minimum stirring used. The total polymerization time was varied to attain the target inherent viscosities. After the polymerization was complete, the Belmont metal bath was lowered and the polymer was allowed to cool to below its glass transition temperature. After about 30 minutes, the flask was reimmersed in the Belmont metal bath (the temperature had been increased to 295° C. during this 30 minute wait) and the polymer mass was heated until it pulled away from the glass flask. The polymer mass was stirred at mid level in the flask until the polymer had cooled. The polymer was removed from the flask and ground to pass a 3 mm screen. Variations to this procedure were made to produce the copolyesters described below with a targeted composition of 45 mol %.

Inherent viscosities were measured as described in the “Measurement Methods” section above. The compositions of the polyesters were determined by ¹H NMR as explained before in the Measurement Methods section. The glass transition temperatures were determined by DSC, using the second heat after quench at a rate of 20° C./min.

The table below shows the experimental data for the polyesters of this Example. The data shows that cis 2,2,4,4-tetramethyl-1,3-cyclobutanediol is approximately twice as effective as trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol at increasing the glass transition temperature for a constant inherent viscosity. TABLE 6 Effect of 2,2,4,4-tetramethyl-1,3-cyclobutanediol cis/trans composition on T_(g) mol % IV T_(g) η_(o) at 260° C. η_(o) at 275° C. η_(o) at 290° C. % cis Example TMCD (dL/g) (° C.) (Poise) (Poise) (Poise) TMCD A 45.8 0.71 119 N.A. N.A. N.A. 4.1 B 43.2 0.72 122 N.A. N.A. N.A. 22.0 C 46.8 0.57 119 26306 16941 6601 22.8 D 43.0 0.67 125 55060 36747 14410 23.8 E 43.8 0.72 127 101000 62750 25330 24.5 F 45.9 0.533 119 11474 6864 2806 26.4 G 45.0 0.35 107 N.A. N.A. N.A. 27.2 H 41.2 0.38 106 1214 757 N.A. 29.0 I 44.7 0.59 123 N.A. N.A. N.A. 35.4 J 44.4 0.55 118 N.A. N.A. N.A. 35.6 K 44.3 0.51 119 N.A. N.A. N.A. 36.3 L 44.0 0.49 128 N.A. N.A. N.A. 71.7 M 43.6 0.52 128 N.A. N.A. N.A. 72.1 N 43.6 0.54 127 N.A. N.A. N.A. 72.3 O 41.5 0.58 133 15419 10253 4252 88.7 P 43.8 0.57 135 16219 10226 4235 89.6 Q 41.0 0.33 120 521 351 2261 90.4 R 43.0 0.56 134 N.A. N.A. N.A. 90.6 S 43.0 0.49 132 7055 4620 2120 90.6 T 43.1 0.55 134 12970 8443 3531 91.2 U 45.9 0.52 137 N.A. N.A. N.A. 98.1 NA = not available

Example 7

This example illustrates the preparation of a copolyester containing 100 mol % dimethyl terephthalate residues, 55 mol % 1,4-cyclohexanedimethanol residues, and 45 mol % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues.

A mixture of 97.10 g (0.5 mol) dimethyl terephthalate, 52.46 g (0.36 mol) 1,4-cyclohexanedimethanol, 34.07 g (0.24 mol) 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and 0.0863 g (300 ppm) dibutyl tin oxide was placed in a 500-milliliter flask equipped with an inlet for nitrogen, a metal stirrer, and a short distillation column. The flask was placed in a Wood's metal bath already heated to 200° C. The contents of the flask were heated at 200° C. for 1 hour and then the temperature was increased to 210° C. The reaction mixture was held at 210° C. for 2 hours and then heated up to 290° C. in 30 minutes. Once at 290° C., a vacuum of 0.01 psig was gradually applied over the next 3 to 5 minutes. Full vacuum (0.01 psig) was maintained for a total time of about 45 minutes to remove excess unreacted diols. A high melt viscosity, visually clear and colorless polymer was obtained with a glass transition temperature of 125° C. and an inherent viscosity of 0.64 dl/g.

Example 8 Comparative Example

This example illustrates that a polyester based on 100% 2,2,4,4-tetramethyl-1,3-cyclobutanediol has a slow crystallization half-time.

A polyester based solely on terephthalic acid and 2,2,4,4-tetramethyl-1,3-cyclobutanediol was prepared in a method similar to the method described in Example 1A with the properties shown on Table 7. This polyester was made with 300 ppm dibutyl tin oxide. The trans/cis ratio of the 2,2,4,4-tetramethyl-1,3-cyclobutanediol was 65/35.

Films were pressed from the ground polymer at 320° C. Crystallization half-time measurements from the melt were made at temperatures from 220 to 250° C. at 10° C. increments and are reported in Table 7. The fastest crystallization half-time for the sample was taken as the minimum value of crystallization half-time as a function of temperature. The fastest crystallization half-time of this polyester is around 1300 minutes. This value contrasts with the fact that the polyester (PCT) based solely on terephthalic acid and 1,4-cyclohexanedimethanol (no comonomer modification) has an extremely short crystallization half-time (<1 min) as shown in FIG. 1. TABLE 7 Crystallization Half-times (min) at at at at Comonomer IV T_(g) T_(max) 220° C. 230° C. 240° C. 250° C. (mol %) (dl/g) (° C.) (° C.) (min) (min) (min) (min) 100 mol % F 0.63 170.0 330 3291 3066 1303 1888 where: F is 2,2,4,4-Tetramethyl-1,3-cyclobutanediol (65/35 Trans/Cis)

Example 9 Comparative Example

Sheets comprising a polyester that had been prepared with a target composition of 100 mole % terephthalic acid residues, 80 mole % 1,4-cyclohexanedimethanol residues, and 20 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues were produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 177 mil and then various sheets were sheared to size. Inherent viscosity and glass transition temperature were measured on one sheet. The sheet inherent viscosity was measured to be 0.69 dl/g. The glass transition temperature of the sheet was measured to be 106° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 2 weeks. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example G). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 106° C. can be thermoformed under the conditions shown below, as evidenced by these sheets having at least 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Heat Sheet Part Time Temperature Volume Draw Blisters Example (s) (° C.) (mL) (%) (N, L, H) A 86 145 501 64 N B 100 150 500 63 N C 118 156 672 85 N D 135 163 736 94 N E 143 166 760 97 N F 150 168 740 94 L G 159 172 787 100 L

Example 10 Comparative Example

Sheets comprising a polyester that had been prepared with a target composition of 100 mole % terephthalic acid residues, 80 mole % 1,4-cyclohexanedimethanol residues, and 20 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues were produced using a 3.5 inch single screw. A sheet was extruded continuously, gauged to a thickness of 177 mil and then various sheets were sheared to size. Inherent viscosity and glass transition temperature were measured on one sheet. The sheet inherent viscosity was measured to be 0.69 dl/g. The glass transition temperature of the sheet was measured to be 106° C. Sheets were then conditioned at 100% relative humidity and 25° C. for 2 weeks. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 60/40/40% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example G). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 106° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having at least 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Heat Sheet Part Time Temperature Volume Draw Blisters Example (s) (° C.) (mL) (%) (N, L, H) A 141 154 394 53 N B 163 157 606 82 N C 185 160 702 95 N D 195 161 698 95 N E 215 163 699 95 L F 230 168 705 96 L G 274 174 737 100 H H 275 181 726 99 H

Example 11 Comparative Example

Sheets consisting of Kelvx 201 were produced using a 3.5 inch single screw extruder. Kelvx is a blend consisting of 69.85% PCTG (Eastar from Eastman Chemical Co. having 100 mole % terephthalic acid residues, 62 mole % 1,4-cyclohexanedimethanol residues, and 38 mole % ethylene glycol residues); 30% PC (bisphenol A polycarbonate); and 0.15% Weston 619 (stabilizer sold by Crompton Corporation). A sheet was extruded continuously, gauged to a thickness of 177 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 100° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 2 weeks. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example E). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 100° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having at least 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Heat Sheet Part Time Temperature Volume Draw Blisters Example (s) (° C.) (mL) (%) (N, L, H) A 90 146 582 75 N B 101 150 644 83 N C 111 154 763 98 N D 126 159 733 95 N E 126 159 775 100 N F 141 165 757 98 N G 148 168 760 98 L

Example 12 Comparative Example

Sheets consisting of Kelvx 201 were produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 177 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 100° C. Sheets were then conditioned at 100% relative humidity and 25° C. for 2 weeks. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 60/40/40% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example H). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 100° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 110 143 185 25 N B 145 149 529 70 N C 170 154 721 95 N D 175 156 725 96 N E 185 157 728 96 N F 206 160 743 98 L G 253 NR 742 98 H H 261 166 756 100 H NR = Not recorded

Example 13 Comparative Example

Sheets consisting of PCTG 25976 (100 mole % terephthalic acid residues, 62 mole % 1,4-cyclohexanedimethanol residues, and 38 mole % ethylene glycol residues) were produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 87° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.17 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 87° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 102 183 816 100 N B 92 171 811 99 N C 77 160 805 99 N D 68 149 804 99 N E 55 143 790 97 N F 57 138 697 85 N

Example 14 Comparative Example

A miscible blend consisting of 20 wt % Teijin L-1250 polycarbonate (a bisphenol-A polycarbonate), 79.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 94° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.25 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 94° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 92 184 844 100 H B 86 171 838 99 N C 73 160 834 99 N D 58 143 787 93 N E 55 143 665 79 N

Example 15 Comparative Example

A miscible blend consisting of 30 wt % Teijin L-1250 polycarbonate, 69.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 99° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.25 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 99° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 128 194 854 100 H B 98 182 831 97 L C 79 160 821 96 N D 71 149 819 96 N E 55 145 785 92 N F 46 143 0 0 NA G 36 132 0 0 NA NA = not applicable. A value of zero indicates that the sheet was not formed because it did not pull into the mold (likely because it was too cold).

Example 16 Comparative Example

A miscible blend consisting of 40 wt % Teijin L-1250 polycarbonate, 59.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 105° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.265 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Examples 8A to 8E). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 105° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 111 191 828 100 H B 104 182 828 100 H C 99 179 827 100 N D 97 177 827 100 N E 78 160 826 100 N F 68 149 759 92 N G 65 143 606 73 N

Example 17 Comparative Example

A miscible blend consisting of 50 wt % Teijin L-1250 polycarbonate, 49.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 111° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.225 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Examples A to D). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 111° C. can be thermoformed under the conditions shown below, as evidenced by the production of sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 118 192 815 100 H B 99 182 815 100 H C 97 177 814 100 L D 87 171 813 100 N E 80 160 802 98 N F 64 154 739 91 N G 60 149 0 0 NA NA = not applicable. A value of zero indicates that the sheet was not formed because it did not pull into the mold (likely because it was too cold).

Example 18 Comparative Example

A miscible blend consisting of 60 wt % Teijin L-1250 polycarbonate, 39.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 117° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.215 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 117° C. cannot be thermoformed under the conditions shown below, as evidenced by the inability to produce sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 114 196 813 100 H B 100 182 804 99 H C 99 177 801 98 L D 92 171 784 96 L E 82 168 727 89 L F 87 166 597 73 N

Example 19 Comparative Example

A miscible blend consisting of 65 wt % Teijin L-1250 polycarbonate, 34.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 120° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.23 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 120° C. cannot be thermoformed under the conditions shown below, as evidenced by the inability to produce sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 120 197 825 100 H B 101 177 820 99 H C 95 174 781 95 L D 85 171 727 88 L E 83 166 558 68 L

Example 20 Comparative Example

A miscible blend consisting of 70 wt % Teijin L-1250 polycarbonate, 29.85 wt % PCTG 25976, and 0.15 wt % Weston 619 was produced using a 1.25 inch single screw extruder. Sheets consisting of the blend were then produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 123° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.205 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw, and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Examples A and B). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 123° C. cannot be thermoformed under the conditions shown below, as evidenced by the inability to produce sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 126 198 826 100 H B 111 188 822 100 H C 97 177 787 95 L D 74 166 161 19 L E 58 154 0 0 NA F 48 149 0 0 NA NA = not applicable. A value of zero indicates that the sheet was not formed because it did not pull into the mold (likely because it was too cold).

Example 21 Comparative Example

Sheets consisting of Teijin L-1250 polycarbonate were produced using a 3.5 inch single screw extruder. A sheet was extruded continuously, gauged to a thickness of 118 mil and then various sheets were sheared to size. The glass transition temperature was measured on one sheet and was 149° C. Sheets were then conditioned at 50% relative humidity and 60° C. for 4 weeks. The moisture level was measured to be 0.16 wt %. Sheets were subsequently thermoformed into a female mold having a draw ratio of 2.5:1 using a Brown thermoforming machine. The thermoforming oven heaters were set to 70/60/60% output using top heat only. Sheets were left in the oven for various amounts of time in order to determine the effect of sheet temperature on the part quality as shown in the table below. Part quality was determined by measuring the volume of the thermoformed part, calculating the draw and visually inspecting the thermoformed part. The draw was calculated as the part volume divided by the maximum part volume achieved in this set of experiments (Example A). The thermoformed part was visually inspected for any blisters and the degree of blistering rated as none (N), low (L), or high (H). The results below demonstrate that these thermoplastic sheets with a glass transition temperature of 149° C. cannot be thermoformed under the conditions shown below, as evidenced by the inability to produce sheets having greater than 95% draw and no blistering, without predrying the sheets prior to thermoforming. Thermoforming Conditions Part Quality Sheet Part Heat Temperature Volume Blisters Example Time (s) (° C.) (mL) Draw (%) (N, L, H) A 152 216 820 100 H B 123 193 805 98 H C 113 191 179 22 H D 106 188 0 0 H E 95 182 0 0 NA F 90 171 0 0 NA NA = not applicable. A value of zero indicates that the sheet was not formed because it did not pull into the mold (likely because it was too cold).

It can be clearly seen from a comparison of the data in the above relevant working examples that the polyesters of the present invention offer a definite advantage over the commercially available polyesters with regard to glass transition temperature, density, slow crystallization rate, melt viscosity, and toughness.

The invention has been described in detail with reference to the embodiments disclosed herein, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 

1. A film or sheet comprising a comprising at least one polyester which comprises: (a) a dicarboxylic acid component comprising: i) 70 to 100 mole % of terephthalic acid residues; ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (b) a glycol component comprising: i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues, wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and wherein the inherent viscosity of said polyester is 0.50 to 0.68 dL/g as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.
 2. The film or sheet of claim 1, wherein the inherent viscosity of said polyester is from 0.50 to less than 0.68 dL/g.
 3. The film or sheet of claim 1, wherein the inherent viscosity of said polyester is from 0.50 to 0.65 dL/g.
 4. The film or sheet of claim 1, wherein the inherent viscosity of said polyester is from 0.55 to 0.68 dL/g.
 5. The film or sheet of claim 1, wherein the inherent viscosity of said polyester is from 0.58 to 0.68 dL/g.
 6. The film or sheet of claim 1, wherein said polyester has a Tg of 85 to 200° C.
 7. The film or sheet of claim 1, wherein said polyester has a Tg of 110 to 200° C.
 8. The film or sheet of claim 1, wherein said polyester has a Tg of 110 to 170° C.
 9. The film or sheet of claim 1, wherein said polyester has a Tg of 110 to 160° C.
 10. The film or sheet of claim 1, wherein said polyester has a Tg of 110 to 150° C.
 11. The film or sheet of claim 1, wherein said polyester has a Tg of 120 to 160° C.
 12. The film or sheet of claim 1, wherein said polyester has a Tg of 120 to 150° C.
 13. The film or sheet of claim 1, wherein said polyester has a Tg of 130 to 160° C.
 14. The film or sheet of claim 1, wherein said polyester has a Tg of 130 to 150° C.
 15. The film or sheet of claim 1, wherein said polyester has a Tg of 130 to 145° C.
 16. The film or sheet of claim 1, wherein said polyester has a Tg of 140 to 150° C.
 17. The film or sheet of claim 1, wherein said polyester has a Tg of 135 to 145° C.
 18. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 40 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 60 mole % 1,4-cyclohexanedimethanol.
 19. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 40 to 64.9 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35.1 to 60 mole % 1,4-cyclohexanedimethanol.
 20. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 40 to 65 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 35 to 60 mole % 1,4-cyclohexanedimethanol.
 21. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 40 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 60 mole % 1,4-cyclohexanedimethanol.
 22. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 45 to 60 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 40 to 55 mole % 1,4-cyclohexanedimethanol.
 23. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 45 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 55 mole % 1,4-cyclohexanedimethanol.
 24. The film or sheet of claim 1, wherein the glycol component of said polyester comprises 46 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to 55 mole % 1,4-cyclohexanedimethanol.
 25. The film or sheet of claim 1, wherein the glycol component of said polyester comprises greater than 46 to 55 mole % 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 45 to less than 55 mole % 1,4-cyclohexanedimethanol.
 26. The film or sheet of claim 1, wherein the dicarboxylic acid component comprises 80 to 100 mole % of terephthalic acid, an ester thereof, or a mixture thereof.
 27. The film or sheet of claim 1, wherein the dicarboxylic acid component comprises 90 to 100 mole % of terephthalic acid, an ester thereof, or a mixture thereof.
 28. The film or sheet of claim 1, wherein the dicarboxylic acid component comprises 95 to 100 mole % of terephthalic acid, an ester thereof, or a mixture thereof.
 29. The film or sheet of claim 1, wherein said polyester comprises 1,3-propanediol, 1,4-butanediol, or mixtures thereof.
 30. The film or sheet of claim 1, wherein said polyester comprises less than 15 mole % of residues from at least one modifying glycol.
 31. The film or sheet of claim 30, wherein said polyester comprises less than 15 mole % of ethylene glycol residues.
 32. The film or sheet of claim, wherein said polyester comprises 2,2,4,4-tetramethyl-1,3-cyclobutanediol in the pure cis form, the pure trans form, or mixtures of the cis and trans forms.
 33. The film or sheet of claim 1, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a mixture comprising greater than 50 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and less than 50 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol.
 34. The film or sheet of claim 1, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a mixture comprising greater than 55 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and less than 45 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol.
 35. The film or sheet of claim 1, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a mixture comprising greater than 70 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol and less than 30 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol.
 36. The film or sheet of claim 1, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a mixture comprising 30 to 70 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol and 30 to 70 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol.
 37. The film or sheet of claim 1, wherein said 2,2,4,4-tetramethyl-1,3-cyclobutanediol is a mixture comprising 50 to 70 mole % of trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol and 30 to 50 mole % of cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol.
 38. The film or sheet of claim 1, wherein said polyester composition comprises at least one polymer chosen from the polyester composition of claim 1, further comprising at least one polymer selected from nylons; polyesters different than those in claim 1; polyamides; polystyrene; polystyrene copolymers; styrene acrylonitrile copolymers; acrylonitrile butadiene styrene copolymers; poly(methylmethacrylate); acrylic copolymers; poly(ether-imides); polyphenylene oxides, such as poly(2,6-dimethylphenylene oxide); or poly(phenylene oxide)/polystyrene blends; polyphenylene sulfides; polyphenylene sulfide/sulfones; poly(ester-carbonates); polycarbonates; polysulfones; polysulfone ethers; and poly(ether-ketones) of aromatic dihydroxy compounds or mixtures thereof.
 39. The film or sheet of claim 1, wherein said polyester comprises a branching agent for the polyester.
 40. The film or sheet of claim 1, wherein said polyester is linear.
 41. The film or sheet of claim 1, wherein said polyester composition comprises at least one polycarbonate.
 42. The film or sheet of claim 1, wherein said polyester comprises a branching agent for the polycarbonate.
 43. The film or sheet of claim 1, wherein said polyester comprises a branching agent in an amount of 0.01 to 10 weight % based on the total mole percentage of the diol or diacid residues.
 44. The film or sheet of claim 1, wherein said polyester comprises a branching agent in an amount of 0.01 to 5 weight % based on the total mole percentage of the diol or diacid residues.
 45. The film or sheet of claim 1, wherein the melt viscosity of said polyester is less than 30,000 poise as measured at 1 radian/second on a rotary melt rheometer at 290° C.
 46. The film or sheet of claim 1, wherein the melt viscosity of said polyester is less than 20,000 poise as measured at 1 radian/second on a rotary melt rheometer at 290° C.
 47. The film or sheet of claim 1, wherein said polyester has a crystallization half-time greater than 5 minutes at 170° C.
 48. The film or sheet of claim 1, wherein said polyester has a crystallization half-time of greater than 1,000 minutes at 170° C.
 49. The film or sheet of claim 1, wherein said polyester has a crystallization half-time of greater than 10,000 minutes at 170° C.
 50. The film or sheet of claim 1, wherein said polyester composition has a density of 1.10 to less than 1.2 g/ml at 23° C.
 51. The film or sheet of claim 1, wherein said polyester composition has a density of 1.13 to less than 1.18 g/ml at 23° C.
 52. The film or sheet of claim 1, wherein said polyester composition comprises at least one thermal stabilizer or reaction products thereof.
 53. The film or sheet of claim 1, wherein the yellowness index of said polyester according to ASTM D-1925 is less than
 50. 54. The film or sheet of claim 1, wherein the b* value of said polyester is from 0 to less than
 10. 55. The film or sheet of claim 1, wherein the L* value of said polyester is from 50 to
 90. 56. The film or sheet of claim 1, wherein the b* value of said polyester is from 0 to less than 10 and the L* value of said polyester is from 50 to
 90. 57. The film or sheet of claim 1, wherein said polyester has a notched Izod impact strength of at least 3 ft-lbs/in at 23° C. according to ASTM D256 with a 10-mil notch in a ⅛-inch thick bar.
 58. The film or sheet of claim 1, wherein said polyester has a notched Izod impact strength of at least 10 ft-lbs/in at 23° C. according to ASTM D256 with a 10-mil notch in a ⅛-inch thick bar.
 59. The film or sheet of claim 1, wherein the polyester comprises at least one catalyst comprising a tin compound or a reaction product thereof and/or residues thereof.
 60. The film or sheet of claim 1, wherein the polyester comprises at least one chain extender.
 61. The film or sheet of claim 1, wherein the polyester comprises an additive chosen from at least one of the following: colorants, dyes, mold release agents, flame retardants, plasticizers, nucleating agents, UV stabilizers, thermal stabilizers and/or reaction products thereof, fillers, and impact modifiers.
 62. A film or sheet comprising a polyester composition which comprises: (I) at least one polyester which comprises: (a) a dicarboxylic acid component comprising: i) 70 to 100 mole % of terephthalic acid residues; ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (b) a glycol component comprising: i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues, and (II) at least one branching agent or residues thereof; wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and wherein the inherent viscosity of said polyester is 0.5 to 1.2 dL/g as determined in 60/40 (wt/wt)phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C.
 63. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 1.2 dL/g.
 64. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 1.1 dL/g.
 65. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 1 dL/g.
 66. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 0.9 dL/g.
 67. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 0.8 dL/g.
 68. The film or sheet of claim 62, wherein the inherent viscosity of said polyester is from 0.50 to 0.75 dL/g.
 69. A film or sheet comprising a polyester composition which comprise: (I) at least one polyester which comprises: (a) a dicarboxylic acid component comprising: i) 70 to 100 mole % of terephthalic acid residues; ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (b) a glycol component comprising: i) 40 to 65 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and ii) 35 to 60 mole % of 1,4-cyclohexanedimethanol residues; and (II) at least one thermal stabilizer or reaction products thereof; wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and wherein the inherent viscosity of said polyester is 0.5 to 1.2 dL/g as determined in 60/40 (wt/wt)phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C. 